Ok. Well I am just playing with some code here trying to get some data from a .MDB to bind with a DataGrid, ListBox, and a ComboBox. I have one button for to bind data to the DataGrid, another for the ListBox and a third one for the ComboBox.
Then, the code I am using is:
Code:
Imports System.Data.OleDb
Public Class frmMain
Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
' Creating connection and command sting
Dim conStr As String = "Provider=Microsoft.JET.OLEDB.4.0;data source=C:\Documents and Settings\HP_Administrator\My Documents\Visual Studio Projects\Teacher Assistant ver. 0.0.1\TeacherAssistant_dbTest.mdb"
Dim sqlStr As String = "SELECT * FROM StudentName"
' Create connection object
Dim conn As OleDBConnection = New OleDBConnection(conStr)
' Create data adapter object
Dim da As OleDbDataAdapter = New OleDbDataAdapter(sqlStr, conn)
' Create a DataSet1 object and fill with data using data adapter's Fill method
Dim ds As DataSet1 = New DataSet
da.Fill(ds, "StudentName")
' Attach DataSet1's DefaultView to the datagrid control
DataGrid1.DataSource = ds.DefaultViewManager
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
' Creating connection and command sting
Dim conStr As String = "Provider=Microsoft.JET.OLEDB.4.0;data source=C:\Documents and Settings\HP_Administrator\My Documents\Visual Studio Projects\Teacher Assistant ver. 0.0.1\TeacherAssistant_dbTest.mdb"
Dim sqlStr As String = "SELECT * FROM StudentName"
' Create connection object
Dim conn As OleDBConnection = New OleDBConnection(conStr)
' Create data adapter object
Dim da As OleDbDataAdapter = New OleDbDataAdapter(sqlStr, conn)
' Create a DataSet1 object and fill with data using data adapter's Fill method
Dim ds As DataSet1 = New DataSet
da.Fill(ds, "StudentName")
' Attach DataSet1's DefaultView to the datagrid control
Dim dv As DataView = ds.Tables("StudentName").DefaultView
ListBox1.DataSource = dv
ListBox1.DisplayMember = "FirstName"
End Sub
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
' Creating connection and command sting
Dim conStr As String = "Provider=Microsoft.JET.OLEDB.4.0;data source=C:\Documents and Settings\HP_Administrator\My Documents\Visual Studio Projects\Teacher Assistant ver. 0.0.1\TeacherAssistant_dbTest.mdb"
Dim sqlStr As String = "SELECT * FROM StudentName"
' Create connection object
Dim conn As OleDBConnection = New OleDBConnection(conStr)
' Create data adapter object
Dim da As OleDbDataAdapter = New OleDbDataAdapter(sqlStr, conn)
' Create a DataSet1 object and fill with data using data adapter's Fill method
Dim ds As DataSet1 = New DataSet
da.Fill(ds, "StudentName")
' Attach DataSet1's DefaultView to the datagrid control
Dim dv As DataView = ds.Tables("StudentName").DefaultView
ComboBox1.DataSource = dv
ComboBox1.DisplayMember = "FirstName"
End Sub
End Class
But, I keep getting the following error message:
Quote:
quote:An unhandled exception of type 'System.InvalidCastException' occurred in ApplicationName.exe
Additional information: Specified cast is not valid.
|
What do I need to do to fix that error?