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Old May 6th, 2005, 06:08 AM
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Default Problem with datareader

hi,

 i am writing code like the below

     dr=cmd.executereader
     dr.read()
     a=dr.item(0)

  where dr is datareader and a is a variable.when i get the data into datareader this code was working properly.

    but when no data was coming from databse to datareader the code is not working.it was showing a error("reading when nodata present").

     so how can i see whether i got data into datareader or not..?

 thanks in advance-Ashok Parchuri
 
Old May 6th, 2005, 07:05 AM
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If dr.read() then
   a=dr.item(0)
end if

Read() will return true until there are no more rows.

-Peter
 
Old May 13th, 2005, 04:32 AM
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Purpose :To retrieve data from the database using Data Reader and Data Commands. When this code is executed, the data in a database is displayed in two textbox controls.

Preparation:

Design a form using .NET environment and place two textbox controls on a form.
Design and create a table using SQL Server 2000.

Name the Database as FinAccounting.
Name the Table as AccountsTable.
Name the form as Form1
Name the controls on the form as Textbox1 and Textbox2.

Tasks:

1. Establish the connection with the Database using Connection object.
2. Execute the command.
3. The data will be read by the Datareader object and the contents of the first record is displayed in the textboxes.

Imports System.Data.SqlClient
    Public Class Form1
        Inherits System.Windows.Forms.Form
        Dim str_sql_user_select As String = “SELECT * FROM AccountsTable”
        Dim str_connection As String = “Data Source=VSDOTNET;Integrated Security=SSPI;Initial Catalog=FinAccounting”
        Dim mycon As SqlConnection
        Dim comUserSelect As SqlCommand
        Dim myreader As SqlDataReader

Private Sub Form1_Load(ByVal sender As Object, ByVal e As system.EventArgs) Handles
        MyBase.Load
        mycon = New SqlConnection(str_connection)
        â€˜Instantiate the commands
        comUserSelect = New SqlCommand(str_sql_user_select, mycon)
        TextBox1.Text = “ “
        TextBox2.Text = “ “
            mycon.Open()
            myreader = comUserSelect.ExecuteReader
            If (myreader.Read = True) Then
                TextBox1.Text = myreader(0)
                TextBox2.Text = myreader(1)
            Else
                MsgBox(“You have reached eof”)
            End If
        End Sub
End Class

Regards
Bhar
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