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aspx_beginners thread: DataGrid problem
Message #1 by timofey@e... on Sun, 12 Jan 2003 08:38:15
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Hi everyone:
I am new to ASP.NET please bear with me.
I have WebForm and DataGrid control with Load button. The code as follows:
Public Class DataWebForm1
Inherits System.Web.UI.Page
Protected WithEvents OleDbSelectCommand1 As
System.Data.OleDb.OleDbCommand
Protected WithEvents OleDbInsertCommand1 As
System.Data.OleDb.OleDbCommand
Protected WithEvents objdsCustomers As Introduction.dsCustomers
Protected WithEvents OleDbConnection1 As
System.Data.OleDb.OleDbConnection
Protected WithEvents OleDbDataAdapter1 As
System.Data.OleDb.OleDbDataAdapter
Protected WithEvents buttonLoad As System.Web.UI.WebControls.Button
Protected WithEvents masterDataGrid As
System.Web.UI.WebControls.DataGrid
#Region " Web Form Designer Generated Code "
'This call is required by the Web Form Designer.
<System.Diagnostics.DebuggerStepThrough()> Private Sub
InitializeComponent()
Me.OleDbSelectCommand1 = New System.Data.OleDb.OleDbCommand()
Me.OleDbConnection1 = New System.Data.OleDb.OleDbConnection()
Me.OleDbInsertCommand1 = New System.Data.OleDb.OleDbCommand()
'
'OleDbSelectCommand1
'
Me.OleDbSelectCommand1.CommandText = "SELECT CustomerID,
CompanyName, ContactName, ContactTitle, Address, City, Region," & _
" PostalCode, Country, Phone, Fax FROM Customers"
Me.OleDbSelectCommand1.Connection = Me.OleDbConnection1
'
'OleDbConnection1
'
Me.OleDbConnection1.ConnectionString
= "Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security
Info=False;Initial " & _
"Catalog=Northwind;Data Source=SERVER-KMSX8EHG\NETSDK;Use
Procedure for Prepare=1" & _
";Auto Translate=True;Packet Size=4096;Workstation ID=SERVER-
KMSX8EHG;Use Encrypt" & _
"ion for Data=False;Tag with column collation when possible=False"
'
'OleDbInsertCommand1
'
Me.OleDbInsertCommand1.CommandText = "INSERT INTO Customers
(CustomerID, CompanyName, ContactName, ContactTitle, Address" & _
", City, Region, PostalCode, Country, Phone, Fax) VALUES
(?, ?, ?, ?, ?, ?, ?, ?," & _
" ?, ?, ?); SELECT CustomerID, CompanyName, ContactName,
ContactTitle, Address, C" & _
"ity, Region, PostalCode, Country, Phone, Fax FROM Customers"
Me.OleDbInsertCommand1.Connection = Me.OleDbConnection1
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("CustomerID",
System.Data.OleDb.OleDbType.VarWChar, 5, "CustomerID"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("CompanyName",
System.Data.OleDb.OleDbType.VarWChar, 40, "CompanyName"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("ContactName",
System.Data.OleDb.OleDbType.VarWChar, 30, "ContactName"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("ContactTitle",
System.Data.OleDb.OleDbType.VarWChar, 30, "ContactTitle"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("Address",
System.Data.OleDb.OleDbType.VarWChar, 60, "Address"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("City",
System.Data.OleDb.OleDbType.VarWChar, 15, "City"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("Region",
System.Data.OleDb.OleDbType.VarWChar, 15, "Region"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("PostalCode",
System.Data.OleDb.OleDbType.VarWChar, 10, "PostalCode"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("Country",
System.Data.OleDb.OleDbType.VarWChar, 15, "Country"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("Phone",
System.Data.OleDb.OleDbType.VarWChar, 24, "Phone"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("Fax",
System.Data.OleDb.OleDbType.VarWChar, 24, "Fax"))
End Sub
Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Init
'CODEGEN: This method call is required by the Web Form Designer
'Do not modify it using the code editor.
InitializeComponent()
End Sub
#End Region
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
'Put user code to initialize the page here
End Sub
Private Sub buttonLoad_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles buttonLoad.Click
Try
Me.LoadDataSet()
Me.masterDataGrid.SelectedIndex = -1
Me.masterDataGrid.DataBind()
Catch eLoad As System.Exception
Me.Response.Write(eLoad.Message)
End Try
End Sub
Public Sub LoadDataSet()
'Create a new dataset to hold the records returned from the call
to FillDataSet.
'A temporary dataset is used because filling the existing dataset
would
'require the databindings to be rebound.
Dim objDataSetTemp As Introduction.dsCustomers
objDataSetTemp = New Introduction.dsCustomers()
Try
'Attempt to fill the temporary dataset.
Me.FillDataSet(objDataSetTemp)
Catch eFillDataSet As System.Exception
'Add your error handling code here.
Throw eFillDataSet
End Try
Try
'Empty the old records from the dataset.
objdsCustomers.Clear()
'Merge the records into the main dataset.
objdsCustomers.Merge(objDataSetTemp)
Catch eLoadMerge As System.Exception
'Add your error handling code here.
Throw eLoadMerge
End Try
End Sub
Public Sub FillDataSet(ByVal dataSet As Introduction.dsCustomers)
'Turn off constraint checking before the dataset is filled.
'This allows the adapters to fill the dataset without concern
'for dependencies between the tables.
dataSet.EnforceConstraints = False
Try
'Open the connection.
Me.OleDbConnection1.Open()
'Attempt to fill the dataset through the OleDbDataAdapter1.
Me.OleDbDataAdapter1.Fill(dataSet)
Catch fillException As System.Exception
'Add your error handling code here.
Throw fillException
Finally
'Turn constraint checking back on.
dataSet.EnforceConstraints = True
'Close the connection whether or not the exception was thrown.
Me.OleDbConnection1.Close()
End Try
End Sub
End Class
After Button_Click event, I am getting the following message:
Object reference not set to an instance of an object.
What I am missing here.
TIA
Sam
Message #2 by "Jack" <jdunstan7@h...> on Mon, 13 Jan 2003 12:28:08 -0500
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Sam,
I don't see in your code snippet where you set the masterDataGrid.source. That could be the problem.
hth
Jack
----- Original Message -----
From: timofey@e...
To: aspx_beginners
Sent: Sunday, January 12, 2003 8:38 AM
Subject: [aspx_beginners] DataGrid problem
Hi everyone:
I am new to ASP.NET please bear with me.
I have WebForm and DataGrid control with Load button. The code as follows:
Public Class DataWebForm1
Inherits System.Web.UI.Page
Protected WithEvents OleDbSelectCommand1 As
System.Data.OleDb.OleDbCommand
Protected WithEvents OleDbInsertCommand1 As
System.Data.OleDb.OleDbCommand
Protected WithEvents objdsCustomers As Introduction.dsCustomers
Protected WithEvents OleDbConnection1 As
System.Data.OleDb.OleDbConnection
Protected WithEvents OleDbDataAdapter1 As
System.Data.OleDb.OleDbDataAdapter
Protected WithEvents buttonLoad As System.Web.UI.WebControls.Button
Protected WithEvents masterDataGrid As
System.Web.UI.WebControls.DataGrid
#Region " Web Form Designer Generated Code "
'This call is required by the Web Form Designer.
<System.Diagnostics.DebuggerStepThrough()> Private Sub
InitializeComponent()
Me.OleDbSelectCommand1 = New System.Data.OleDb.OleDbCommand()
Me.OleDbConnection1 = New System.Data.OleDb.OleDbConnection()
Me.OleDbInsertCommand1 = New System.Data.OleDb.OleDbCommand()
'
'OleDbSelectCommand1
'
Me.OleDbSelectCommand1.CommandText = "SELECT CustomerID,
CompanyName, ContactName, ContactTitle, Address, City, Region," & _
" PostalCode, Country, Phone, Fax FROM Customers"
Me.OleDbSelectCommand1.Connection = Me.OleDbConnection1
'
'OleDbConnection1
'
Me.OleDbConnection1.ConnectionString
= "Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security
Info=False;Initial " & _
"Catalog=Northwind;Data Source=SERVER-KMSX8EHG\NETSDK;Use
Procedure for Prepare=1" & _
";Auto Translate=True;Packet Size=4096;Workstation ID=SERVER-
KMSX8EHG;Use Encrypt" & _
"ion for Data=False;Tag with column collation when possible=False"
'
'OleDbInsertCommand1
'
Me.OleDbInsertCommand1.CommandText = "INSERT INTO Customers
(CustomerID, CompanyName, ContactName, ContactTitle, Address" & _
", City, Region, PostalCode, Country, Phone, Fax) VALUES
(?, ?, ?, ?, ?, ?, ?, ?," & _
" ?, ?, ?); SELECT CustomerID, CompanyName, ContactName,
ContactTitle, Address, C" & _
"ity, Region, PostalCode, Country, Phone, Fax FROM Customers"
Me.OleDbInsertCommand1.Connection = Me.OleDbConnection1
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("CustomerID",
System.Data.OleDb.OleDbType.VarWChar, 5, "CustomerID"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("CompanyName",
System.Data.OleDb.OleDbType.VarWChar, 40, "CompanyName"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("ContactName",
System.Data.OleDb.OleDbType.VarWChar, 30, "ContactName"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("ContactTitle",
System.Data.OleDb.OleDbType.VarWChar, 30, "ContactTitle"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("Address",
System.Data.OleDb.OleDbType.VarWChar, 60, "Address"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("City",
System.Data.OleDb.OleDbType.VarWChar, 15, "City"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("Region",
System.Data.OleDb.OleDbType.VarWChar, 15, "Region"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("PostalCode",
System.Data.OleDb.OleDbType.VarWChar, 10, "PostalCode"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("Country",
System.Data.OleDb.OleDbType.VarWChar, 15, "Country"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("Phone",
System.Data.OleDb.OleDbType.VarWChar, 24, "Phone"))
Me.OleDbInsertCommand1.Parameters.Add(New
System.Data.OleDb.OleDbParameter("Fax",
System.Data.OleDb.OleDbType.VarWChar, 24, "Fax"))
End Sub
Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Init
'CODEGEN: This method call is required by the Web Form Designer
'Do not modify it using the code editor.
InitializeComponent()
End Sub
#End Region
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
'Put user code to initialize the page here
End Sub
Private Sub buttonLoad_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles buttonLoad.Click
Try
Me.LoadDataSet()
Me.masterDataGrid.SelectedIndex = -1
Me.masterDataGrid.DataBind()
Catch eLoad As System.Exception
Me.Response.Write(eLoad.Message)
End Try
End Sub
Public Sub LoadDataSet()
'Create a new dataset to hold the records returned from the call
to FillDataSet.
'A temporary dataset is used because filling the existing dataset
would
'require the databindings to be rebound.
Dim objDataSetTemp As Introduction.dsCustomers
objDataSetTemp = New Introduction.dsCustomers()
Try
'Attempt to fill the temporary dataset.
Me.FillDataSet(objDataSetTemp)
Catch eFillDataSet As System.Exception
'Add your error handling code here.
Throw eFillDataSet
End Try
Try
'Empty the old records from the dataset.
objdsCustomers.Clear()
'Merge the records into the main dataset.
objdsCustomers.Merge(objDataSetTemp)
Catch eLoadMerge As System.Exception
'Add your error handling code here.
Throw eLoadMerge
End Try
End Sub
Public Sub FillDataSet(ByVal dataSet As Introduction.dsCustomers)
'Turn off constraint checking before the dataset is filled.
'This allows the adapters to fill the dataset without concern
'for dependencies between the tables.
dataSet.EnforceConstraints = False
Try
'Open the connection.
Me.OleDbConnection1.Open()
'Attempt to fill the dataset through the OleDbDataAdapter1.
Me.OleDbDataAdapter1.Fill(dataSet)
Catch fillException As System.Exception
'Add your error handling code here.
Throw fillException
Finally
'Turn constraint checking back on.
dataSet.EnforceConstraints = True
'Close the connection whether or not the exception was thrown.
Me.OleDbConnection1.Close()
End Try
End Sub
End Class
After Button_Click event, I am getting the following message:
Object reference not set to an instance of an object.
What I am missing here.
TIA
Sam
Message #3 by "Pacific" <timofey@e...> on Mon, 13 Jan 2003 21:44:59 -0800
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Hi Jack:
That's exactly what I was trying to figure out how to do it. Should it be
hard coded or it can be done the other way. In my masterDataGrid Property I
have only one avalable choise Data Source: (unbound). Please guide me how it
should be done. I don't have any ASP.NET books with me. Only internet for
reference.
TIA
Sam
----- Original Message -----
From: "Jack" <jdunstan7@h...>
To: "aspx_beginners" <aspx_beginners@p...>
Sent: Monday, January 13, 2003 9:28 AM
Subject: [aspx_beginners] Re: DataGrid problem
> Sam,
>
> I don't see in your code snippet where you set the masterDataGrid.source.
That could be the problem.
>
> hth
> Jack
>
> ----- Original Message -----
> From: timofey@e...
> To: aspx_beginners
> Sent: Sunday, January 12, 2003 8:38 AM
> Subject: [aspx_beginners] DataGrid problem
>
>
> Hi everyone:
>
> I am new to ASP.NET please bear with me.
>
> I have WebForm and DataGrid control with Load button. The code as
follows:
>
> Public Class DataWebForm1
> Inherits System.Web.UI.Page
> Protected WithEvents OleDbSelectCommand1 As
> System.Data.OleDb.OleDbCommand
> Protected WithEvents OleDbInsertCommand1 As
> System.Data.OleDb.OleDbCommand
> Protected WithEvents objdsCustomers As Introduction.dsCustomers
> Protected WithEvents OleDbConnection1 As
> System.Data.OleDb.OleDbConnection
> Protected WithEvents OleDbDataAdapter1 As
> System.Data.OleDb.OleDbDataAdapter
> Protected WithEvents buttonLoad As System.Web.UI.WebControls.Button
> Protected WithEvents masterDataGrid As
> System.Web.UI.WebControls.DataGrid
>
> #Region " Web Form Designer Generated Code "
>
> 'This call is required by the Web Form Designer.
> <System.Diagnostics.DebuggerStepThrough()> Private Sub
> InitializeComponent()
> Me.OleDbSelectCommand1 = New System.Data.OleDb.OleDbCommand()
> Me.OleDbConnection1 = New System.Data.OleDb.OleDbConnection()
> Me.OleDbInsertCommand1 = New System.Data.OleDb.OleDbCommand()
> '
> 'OleDbSelectCommand1
> '
> Me.OleDbSelectCommand1.CommandText = "SELECT CustomerID,
> CompanyName, ContactName, ContactTitle, Address, City, Region," & _
> " PostalCode, Country, Phone, Fax FROM Customers"
> Me.OleDbSelectCommand1.Connection = Me.OleDbConnection1
> '
> 'OleDbConnection1
> '
> Me.OleDbConnection1.ConnectionString
> = "Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security
> Info=False;Initial " & _
> "Catalog=Northwind;Data Source=SERVER-KMSX8EHG\NETSDK;Use
> Procedure for Prepare=1" & _
> ";Auto Translate=True;Packet Size=4096;Workstation ID=SERVER-
> KMSX8EHG;Use Encrypt" & _
> "ion for Data=False;Tag with column collation when
possible=False"
> '
> 'OleDbInsertCommand1
> '
> Me.OleDbInsertCommand1.CommandText = "INSERT INTO Customers
> (CustomerID, CompanyName, ContactName, ContactTitle, Address" & _
> ", City, Region, PostalCode, Country, Phone, Fax) VALUES
> (?, ?, ?, ?, ?, ?, ?, ?," & _
> " ?, ?, ?); SELECT CustomerID, CompanyName, ContactName,
> ContactTitle, Address, C" & _
> "ity, Region, PostalCode, Country, Phone, Fax FROM Customers"
> Me.OleDbInsertCommand1.Connection = Me.OleDbConnection1
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("CustomerID",
> System.Data.OleDb.OleDbType.VarWChar, 5, "CustomerID"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("CompanyName",
> System.Data.OleDb.OleDbType.VarWChar, 40, "CompanyName"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("ContactName",
> System.Data.OleDb.OleDbType.VarWChar, 30, "ContactName"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("ContactTitle",
> System.Data.OleDb.OleDbType.VarWChar, 30, "ContactTitle"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("Address",
> System.Data.OleDb.OleDbType.VarWChar, 60, "Address"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("City",
> System.Data.OleDb.OleDbType.VarWChar, 15, "City"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("Region",
> System.Data.OleDb.OleDbType.VarWChar, 15, "Region"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("PostalCode",
> System.Data.OleDb.OleDbType.VarWChar, 10, "PostalCode"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("Country",
> System.Data.OleDb.OleDbType.VarWChar, 15, "Country"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("Phone",
> System.Data.OleDb.OleDbType.VarWChar, 24, "Phone"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("Fax",
> System.Data.OleDb.OleDbType.VarWChar, 24, "Fax"))
>
> End Sub
>
> Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles MyBase.Init
> 'CODEGEN: This method call is required by the Web Form Designer
> 'Do not modify it using the code editor.
> InitializeComponent()
> End Sub
>
> #End Region
>
> Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles MyBase.Load
> 'Put user code to initialize the page here
> End Sub
>
> Private Sub buttonLoad_Click(ByVal sender As System.Object, ByVal e
As
> System.EventArgs) Handles buttonLoad.Click
> Try
> Me.LoadDataSet()
> Me.masterDataGrid.SelectedIndex = -1
> Me.masterDataGrid.DataBind()
> Catch eLoad As System.Exception
> Me.Response.Write(eLoad.Message)
> End Try
>
> End Sub
> Public Sub LoadDataSet()
> 'Create a new dataset to hold the records returned from the call
> to FillDataSet.
> 'A temporary dataset is used because filling the existing
dataset
> would
> 'require the databindings to be rebound.
> Dim objDataSetTemp As Introduction.dsCustomers
> objDataSetTemp = New Introduction.dsCustomers()
> Try
> 'Attempt to fill the temporary dataset.
> Me.FillDataSet(objDataSetTemp)
> Catch eFillDataSet As System.Exception
> 'Add your error handling code here.
> Throw eFillDataSet
> End Try
> Try
> 'Empty the old records from the dataset.
> objdsCustomers.Clear()
> 'Merge the records into the main dataset.
> objdsCustomers.Merge(objDataSetTemp)
> Catch eLoadMerge As System.Exception
> 'Add your error handling code here.
> Throw eLoadMerge
> End Try
>
> End Sub
> Public Sub FillDataSet(ByVal dataSet As Introduction.dsCustomers)
> 'Turn off constraint checking before the dataset is filled.
> 'This allows the adapters to fill the dataset without concern
> 'for dependencies between the tables.
> dataSet.EnforceConstraints = False
> Try
> 'Open the connection.
> Me.OleDbConnection1.Open()
> 'Attempt to fill the dataset through the OleDbDataAdapter1.
> Me.OleDbDataAdapter1.Fill(dataSet)
> Catch fillException As System.Exception
> 'Add your error handling code here.
> Throw fillException
> Finally
> 'Turn constraint checking back on.
> dataSet.EnforceConstraints = True
> 'Close the connection whether or not the exception was
thrown.
> Me.OleDbConnection1.Close()
> End Try
>
> End Sub
> End Class
>
>
> After Button_Click event, I am getting the following message:
>
> Object reference not set to an instance of an object.
>
> What I am missing here.
>
> TIA
> Sam
>
>
Message #4 by "Jack" <jdunstan7@h...> on Tue, 14 Jan 2003 15:19:24 -0500
|
|
Sam,
Without knowing for sure what you may be trying to accomplish, normally you set the datagrid's DataSource to a dataset or a
dataview.
Like so:
Private Sub buttonLoad_Click(ByVal sender As System.Object, ByVal e
As
System.EventArgs) Handles buttonLoad.Click
Try
Me.LoadDataSet()
Me.masterDataGrid.SelectedIndex = -1
Me.masterDataGrid.DataSource = objdsCustomers '**** here
Me.masterDataGrid.DataBind()
Catch eLoad As System.Exception
Me.Response.Write(eLoad.Message)
End Try
End Sub
hth
Jack
----- Original Message -----
From: Pacific
To: aspx_beginners
Sent: Tuesday, January 14, 2003 12:44 AM
Subject: [aspx_beginners] Re: DataGrid problem
Hi Jack:
That's exactly what I was trying to figure out how to do it. Should it be
hard coded or it can be done the other way. In my masterDataGrid Property I
have only one avalable choise Data Source: (unbound). Please guide me how it
should be done. I don't have any ASP.NET books with me. Only internet for
reference.
TIA
Sam
----- Original Message -----
From: "Jack" <jdunstan7@h...>
To: "aspx_beginners" <aspx_beginners@p...>
Sent: Monday, January 13, 2003 9:28 AM
Subject: [aspx_beginners] Re: DataGrid problem
> Sam,
>
> I don't see in your code snippet where you set the masterDataGrid.source.
That could be the problem.
>
> hth
> Jack
>
> ----- Original Message -----
> From: timofey@e...
> To: aspx_beginners
> Sent: Sunday, January 12, 2003 8:38 AM
> Subject: [aspx_beginners] DataGrid problem
>
>
> Hi everyone:
>
> I am new to ASP.NET please bear with me.
>
> I have WebForm and DataGrid control with Load button. The code as
follows:
>
> Public Class DataWebForm1
> Inherits System.Web.UI.Page
> Protected WithEvents OleDbSelectCommand1 As
> System.Data.OleDb.OleDbCommand
> Protected WithEvents OleDbInsertCommand1 As
> System.Data.OleDb.OleDbCommand
> Protected WithEvents objdsCustomers As Introduction.dsCustomers
> Protected WithEvents OleDbConnection1 As
> System.Data.OleDb.OleDbConnection
> Protected WithEvents OleDbDataAdapter1 As
> System.Data.OleDb.OleDbDataAdapter
> Protected WithEvents buttonLoad As System.Web.UI.WebControls.Button
> Protected WithEvents masterDataGrid As
> System.Web.UI.WebControls.DataGrid
>
> #Region " Web Form Designer Generated Code "
>
> 'This call is required by the Web Form Designer.
> <System.Diagnostics.DebuggerStepThrough()> Private Sub
> InitializeComponent()
> Me.OleDbSelectCommand1 = New System.Data.OleDb.OleDbCommand()
> Me.OleDbConnection1 = New System.Data.OleDb.OleDbConnection()
> Me.OleDbInsertCommand1 = New System.Data.OleDb.OleDbCommand()
> '
> 'OleDbSelectCommand1
> '
> Me.OleDbSelectCommand1.CommandText = "SELECT CustomerID,
> CompanyName, ContactName, ContactTitle, Address, City, Region," & _
> " PostalCode, Country, Phone, Fax FROM Customers"
> Me.OleDbSelectCommand1.Connection = Me.OleDbConnection1
> '
> 'OleDbConnection1
> '
> Me.OleDbConnection1.ConnectionString
> = "Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security
> Info=False;Initial " & _
> "Catalog=Northwind;Data Source=SERVER-KMSX8EHG\NETSDK;Use
> Procedure for Prepare=1" & _
> ";Auto Translate=True;Packet Size=4096;Workstation ID=SERVER-
> KMSX8EHG;Use Encrypt" & _
> "ion for Data=False;Tag with column collation when
possible=False"
> '
> 'OleDbInsertCommand1
> '
> Me.OleDbInsertCommand1.CommandText = "INSERT INTO Customers
> (CustomerID, CompanyName, ContactName, ContactTitle, Address" & _
> ", City, Region, PostalCode, Country, Phone, Fax) VALUES
> (?, ?, ?, ?, ?, ?, ?, ?," & _
> " ?, ?, ?); SELECT CustomerID, CompanyName, ContactName,
> ContactTitle, Address, C" & _
> "ity, Region, PostalCode, Country, Phone, Fax FROM Customers"
> Me.OleDbInsertCommand1.Connection = Me.OleDbConnection1
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("CustomerID",
> System.Data.OleDb.OleDbType.VarWChar, 5, "CustomerID"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("CompanyName",
> System.Data.OleDb.OleDbType.VarWChar, 40, "CompanyName"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("ContactName",
> System.Data.OleDb.OleDbType.VarWChar, 30, "ContactName"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("ContactTitle",
> System.Data.OleDb.OleDbType.VarWChar, 30, "ContactTitle"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("Address",
> System.Data.OleDb.OleDbType.VarWChar, 60, "Address"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("City",
> System.Data.OleDb.OleDbType.VarWChar, 15, "City"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("Region",
> System.Data.OleDb.OleDbType.VarWChar, 15, "Region"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("PostalCode",
> System.Data.OleDb.OleDbType.VarWChar, 10, "PostalCode"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("Country",
> System.Data.OleDb.OleDbType.VarWChar, 15, "Country"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("Phone",
> System.Data.OleDb.OleDbType.VarWChar, 24, "Phone"))
> Me.OleDbInsertCommand1.Parameters.Add(New
> System.Data.OleDb.OleDbParameter("Fax",
> System.Data.OleDb.OleDbType.VarWChar, 24, "Fax"))
>
> End Sub
>
> Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles MyBase.Init
> 'CODEGEN: This method call is required by the Web Form Designer
> 'Do not modify it using the code editor.
> InitializeComponent()
> End Sub
>
> #End Region
>
> Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles MyBase.Load
> 'Put user code to initialize the page here
> End Sub
>
> Private Sub buttonLoad_Click(ByVal sender As System.Object, ByVal e
As
> System.EventArgs) Handles buttonLoad.Click
> Try
> Me.LoadDataSet()
> Me.masterDataGrid.SelectedIndex = -1
> Me.masterDataGrid.DataBind()
> Catch eLoad As System.Exception
> Me.Response.Write(eLoad.Message)
> End Try
>
> End Sub
> Public Sub LoadDataSet()
> 'Create a new dataset to hold the records returned from the call
> to FillDataSet.
> 'A temporary dataset is used because filling the existing
dataset
> would
> 'require the databindings to be rebound.
> Dim objDataSetTemp As Introduction.dsCustomers
> objDataSetTemp = New Introduction.dsCustomers()
> Try
> 'Attempt to fill the temporary dataset.
> Me.FillDataSet(objDataSetTemp)
> Catch eFillDataSet As System.Exception
> 'Add your error handling code here.
> Throw eFillDataSet
> End Try
> Try
> 'Empty the old records from the dataset.
> objdsCustomers.Clear()
> 'Merge the records into the main dataset.
> objdsCustomers.Merge(objDataSetTemp)
> Catch eLoadMerge As System.Exception
> 'Add your error handling code here.
> Throw eLoadMerge
> End Try
>
> End Sub
> Public Sub FillDataSet(ByVal dataSet As Introduction.dsCustomers)
> 'Turn off constraint checking before the dataset is filled.
> 'This allows the adapters to fill the dataset without concern
> 'for dependencies between the tables.
> dataSet.EnforceConstraints = False
> Try
> 'Open the connection.
> Me.OleDbConnection1.Open()
> 'Attempt to fill the dataset through the OleDbDataAdapter1.
> Me.OleDbDataAdapter1.Fill(dataSet)
> Catch fillException As System.Exception
> 'Add your error handling code here.
> Throw fillException
> Finally
> 'Turn constraint checking back on.
> dataSet.EnforceConstraints = True
> 'Close the connection whether or not the exception was
thrown.
> Me.OleDbConnection1.Close()
> End Try
>
> End Sub
> End Class
>
>
> After Button_Click event, I am getting the following message:
>
> Object reference not set to an instance of an object.
>
> What I am missing here.
>
> TIA
> Sam
>
>
Message #5 by "Pacific" <timofey@e...> on Tue, 14 Jan 2003 22:43:58 -0800
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Hi Jack:
Thank you for your post. Let me look at it.
HTH
Sam
----- Original Message -----
From: "Jack" <jdunstan7@h...>
To: "aspx_beginners" <aspx_beginners@p...>
Sent: Tuesday, January 14, 2003 12:19 PM
Subject: [aspx_beginners] Re: DataGrid problem
> Sam,
>
> Without knowing for sure what you may be trying to accomplish, normally
you set the datagrid's DataSource to a dataset or a dataview.
> Like so:
>
> Private Sub buttonLoad_Click(ByVal sender As System.Object, ByVal e
> As
> System.EventArgs) Handles buttonLoad.Click
> Try
> Me.LoadDataSet()
> Me.masterDataGrid.SelectedIndex = -1
> Me.masterDataGrid.DataSource = objdsCustomers '****
here
> Me.masterDataGrid.DataBind()
> Catch eLoad As System.Exception
> Me.Response.Write(eLoad.Message)
> End Try
>
> End Sub
>
> hth
> Jack
> ----- Original Message -----
> From: Pacific
> To: aspx_beginners
> Sent: Tuesday, January 14, 2003 12:44 AM
> Subject: [aspx_beginners] Re: DataGrid problem
>
>
> Hi Jack:
>
> That's exactly what I was trying to figure out how to do it. Should it
be
> hard coded or it can be done the other way. In my masterDataGrid
Property I
> have only one avalable choise Data Source: (unbound). Please guide me
how it
> should be done. I don't have any ASP.NET books with me. Only internet
for
> reference.
>
> TIA
> Sam
> ----- Original Message -----
> From: "Jack" <jdunstan7@h...>
> To: "aspx_beginners" <aspx_beginners@p...>
> Sent: Monday, January 13, 2003 9:28 AM
> Subject: [aspx_beginners] Re: DataGrid problem
>
>
> > Sam,
> >
> > I don't see in your code snippet where you set the
masterDataGrid.source.
> That could be the problem.
> >
> > hth
> > Jack
> >
> > ----- Original Message -----
> > From: timofey@e...
> > To: aspx_beginners
> > Sent: Sunday, January 12, 2003 8:38 AM
> > Subject: [aspx_beginners] DataGrid problem
> >
> >
> > Hi everyone:
> >
> > I am new to ASP.NET please bear with me.
> >
> > I have WebForm and DataGrid control with Load button. The code as
> follows:
> >
> > Public Class DataWebForm1
> > Inherits System.Web.UI.Page
> > Protected WithEvents OleDbSelectCommand1 As
> > System.Data.OleDb.OleDbCommand
> > Protected WithEvents OleDbInsertCommand1 As
> > System.Data.OleDb.OleDbCommand
> > Protected WithEvents objdsCustomers As Introduction.dsCustomers
> > Protected WithEvents OleDbConnection1 As
> > System.Data.OleDb.OleDbConnection
> > Protected WithEvents OleDbDataAdapter1 As
> > System.Data.OleDb.OleDbDataAdapter
> > Protected WithEvents buttonLoad As
System.Web.UI.WebControls.Button
> > Protected WithEvents masterDataGrid As
> > System.Web.UI.WebControls.DataGrid
> >
> > #Region " Web Form Designer Generated Code "
> >
> > 'This call is required by the Web Form Designer.
> > <System.Diagnostics.DebuggerStepThrough()> Private Sub
> > InitializeComponent()
> > Me.OleDbSelectCommand1 = New
System.Data.OleDb.OleDbCommand()
> > Me.OleDbConnection1 = New
System.Data.OleDb.OleDbConnection()
> > Me.OleDbInsertCommand1 = New
System.Data.OleDb.OleDbCommand()
> > '
> > 'OleDbSelectCommand1
> > '
> > Me.OleDbSelectCommand1.CommandText = "SELECT CustomerID,
> > CompanyName, ContactName, ContactTitle, Address, City, Region," & _
> > " PostalCode, Country, Phone, Fax FROM Customers"
> > Me.OleDbSelectCommand1.Connection = Me.OleDbConnection1
> > '
> > 'OleDbConnection1
> > '
> > Me.OleDbConnection1.ConnectionString
> > = "Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security
> > Info=False;Initial " & _
> > "Catalog=Northwind;Data Source=SERVER-KMSX8EHG\NETSDK;Use
> > Procedure for Prepare=1" & _
> > ";Auto Translate=True;Packet Size=4096;Workstation
ID=SERVER-
> > KMSX8EHG;Use Encrypt" & _
> > "ion for Data=False;Tag with column collation when
> possible=False"
> > '
> > 'OleDbInsertCommand1
> > '
> > Me.OleDbInsertCommand1.CommandText = "INSERT INTO Customers
> > (CustomerID, CompanyName, ContactName, ContactTitle, Address" & _
> > ", City, Region, PostalCode, Country, Phone, Fax) VALUES
> > (?, ?, ?, ?, ?, ?, ?, ?," & _
> > " ?, ?, ?); SELECT CustomerID, CompanyName, ContactName,
> > ContactTitle, Address, C" & _
> > "ity, Region, PostalCode, Country, Phone, Fax FROM
Customers"
> > Me.OleDbInsertCommand1.Connection = Me.OleDbConnection1
> > Me.OleDbInsertCommand1.Parameters.Add(New
> > System.Data.OleDb.OleDbParameter("CustomerID",
> > System.Data.OleDb.OleDbType.VarWChar, 5, "CustomerID"))
> > Me.OleDbInsertCommand1.Parameters.Add(New
> > System.Data.OleDb.OleDbParameter("CompanyName",
> > System.Data.OleDb.OleDbType.VarWChar, 40, "CompanyName"))
> > Me.OleDbInsertCommand1.Parameters.Add(New
> > System.Data.OleDb.OleDbParameter("ContactName",
> > System.Data.OleDb.OleDbType.VarWChar, 30, "ContactName"))
> > Me.OleDbInsertCommand1.Parameters.Add(New
> > System.Data.OleDb.OleDbParameter("ContactTitle",
> > System.Data.OleDb.OleDbType.VarWChar, 30, "ContactTitle"))
> > Me.OleDbInsertCommand1.Parameters.Add(New
> > System.Data.OleDb.OleDbParameter("Address",
> > System.Data.OleDb.OleDbType.VarWChar, 60, "Address"))
> > Me.OleDbInsertCommand1.Parameters.Add(New
> > System.Data.OleDb.OleDbParameter("City",
> > System.Data.OleDb.OleDbType.VarWChar, 15, "City"))
> > Me.OleDbInsertCommand1.Parameters.Add(New
> > System.Data.OleDb.OleDbParameter("Region",
> > System.Data.OleDb.OleDbType.VarWChar, 15, "Region"))
> > Me.OleDbInsertCommand1.Parameters.Add(New
> > System.Data.OleDb.OleDbParameter("PostalCode",
> > System.Data.OleDb.OleDbType.VarWChar, 10, "PostalCode"))
> > Me.OleDbInsertCommand1.Parameters.Add(New
> > System.Data.OleDb.OleDbParameter("Country",
> > System.Data.OleDb.OleDbType.VarWChar, 15, "Country"))
> > Me.OleDbInsertCommand1.Parameters.Add(New
> > System.Data.OleDb.OleDbParameter("Phone",
> > System.Data.OleDb.OleDbType.VarWChar, 24, "Phone"))
> > Me.OleDbInsertCommand1.Parameters.Add(New
> > System.Data.OleDb.OleDbParameter("Fax",
> > System.Data.OleDb.OleDbType.VarWChar, 24, "Fax"))
> >
> > End Sub
> >
> > Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
> > System.EventArgs) Handles MyBase.Init
> > 'CODEGEN: This method call is required by the Web Form
Designer
> > 'Do not modify it using the code editor.
> > InitializeComponent()
> > End Sub
> >
> > #End Region
> >
> > Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
> > System.EventArgs) Handles MyBase.Load
> > 'Put user code to initialize the page here
> > End Sub
> >
> > Private Sub buttonLoad_Click(ByVal sender As System.Object,
ByVal e
> As
> > System.EventArgs) Handles buttonLoad.Click
> > Try
> > Me.LoadDataSet()
> > Me.masterDataGrid.SelectedIndex = -1
> > Me.masterDataGrid.DataBind()
> > Catch eLoad As System.Exception
> > Me.Response.Write(eLoad.Message)
> > End Try
> >
> > End Sub
> > Public Sub LoadDataSet()
> > 'Create a new dataset to hold the records returned from the
call
> > to FillDataSet.
> > 'A temporary dataset is used because filling the existing
> dataset
> > would
> > 'require the databindings to be rebound.
> > Dim objDataSetTemp As Introduction.dsCustomers
> > objDataSetTemp = New Introduction.dsCustomers()
> > Try
> > 'Attempt to fill the temporary dataset.
> > Me.FillDataSet(objDataSetTemp)
> > Catch eFillDataSet As System.Exception
> > 'Add your error handling code here.
> > Throw eFillDataSet
> > End Try
> > Try
> > 'Empty the old records from the dataset.
> > objdsCustomers.Clear()
> > 'Merge the records into the main dataset.
> > objdsCustomers.Merge(objDataSetTemp)
> > Catch eLoadMerge As System.Exception
> > 'Add your error handling code here.
> > Throw eLoadMerge
> > End Try
> >
> > End Sub
> > Public Sub FillDataSet(ByVal dataSet As
Introduction.dsCustomers)
> > 'Turn off constraint checking before the dataset is filled.
> > 'This allows the adapters to fill the dataset without
concern
> > 'for dependencies between the tables.
> > dataSet.EnforceConstraints = False
> > Try
> > 'Open the connection.
> > Me.OleDbConnection1.Open()
> > 'Attempt to fill the dataset through the
OleDbDataAdapter1.
> > Me.OleDbDataAdapter1.Fill(dataSet)
> > Catch fillException As System.Exception
> > 'Add your error handling code here.
> > Throw fillException
> > Finally
> > 'Turn constraint checking back on.
> > dataSet.EnforceConstraints = True
> > 'Close the connection whether or not the exception was
> thrown.
> > Me.OleDbConnection1.Close()
> > End Try
> >
> > End Sub
> > End Class
> >
> >
> > After Button_Click event, I am getting the following message:
> >
> > Object reference not set to an instance of an object.
> >
> > What I am missing here.
> >
> > TIA
> > Sam
> >
> >
>
>
>
>
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