Calling Function

[prav_roy]

hi,
my problem is, i have a class and in that class i have a method to fill datagrid, in one of my form i am creating an object of that class and i m calling the method by passing variables my code looks something like

// My class starts here
Public Class DataControl

Public Sub Gridfill(ByRef grid As DataGrid, ByVal str As String)
Dim cmd As New SqlCommand()
Dim ds As New DataSet()
Dim da As New SqlDataAdapter()
cmd.CommandText = str
cmd.Connection = dbconn
da.SelectCommand = cmd
Dim dt As New DataTable()
da.Fill(ds)
dt = ds.Tables(0)
Dim dv As DataView = New DataView(dt)
grid.DataSource = dv
End Sub
End class
//class ends here

//im calling gridfill method of above class here
Dim datadb As DataControl //object of the class
Private Sub frmSearch_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

Dim stng As String = "select * from viewer_response"

datadb.Gridfill(DataGrid1, stng) //call method
//i get error in above line System.NullReferenceException

End Sub

plz tel me where do i going wrong

 

[Don Delegate]

Try debugging?
Add some exception handling code?

Does DataGrid1 exist?
Does dbConn exist?
Can you open the connection with the sqlserver?

 

[JohnH]

Dim datadb As DataControl //object of the class DataControl is Nothing

Dim datadb As New DataControl //new object instance of the class DataControl