more than one column in a datarelation

[Marivic]

Hello,

All the samples I got only has 1 column that relates 2 tables.

Dim MyDataRelation As DataRelation
MyDataRelation = New DataRelation("BrUserDept", dtBranchUser.Columns("userid"), dtBranchDept.Columns("userid"))
dsUserDept.Relations.Add(MyDataRelation)

How will I relate 2 tables using more than one column?

Thanks in advance.

[Marivic]

Got it!

Sub CreateDataSet()
 
        Dim MyConnection As New SqlConnection()
        MyConnection.ConnectionString = ConfigurationSettings.AppSettings("OpalConnect")
        Try
 
            Dim strSQL As String = "SELECT userid, branchcode, def FROM BranchUser"
            Dim scmd As New SqlCommand(strSQL, MyConnection)
            sda = New SqlDataAdapter(scmd)
            Dim scb As New SqlCommandBuilder(sda)
            scb.GetUpdateCommand()
 
            ' Create a new DataSet and fill its first DataTable.
            dsUserDept = New DataSet()
            sda.Fill(dsUserDept, "BranchUser")
 
            ' Reset the CommandText to get the User dept
            scmd.CommandText = "select userid, branchcode, deptcode, def from BranchDept"
 
            ' Fill the second table in the DataSet.
            sda.Fill(dsUserDept, "BranchDept")
 
            ' Set variables for the DataTables for use later.
            dtBranchUser = dsUserDept.Tables(0)
            dtBranchDept = dsUserDept.Tables(1)
 
            ' Set up DataViews for the DataGrids 
            dvBranchUser = dtBranchUser.DefaultView
            dvBranchDept = dtBranchDept.DefaultView
 
            Dim MyDataRelation As DataRelation
            Dim ParentCols() As DataColumn
            Dim ChildCols() As DataColumn
 
            ParentCols(0) = dtBranchUser.Columns("userid")
            ParentCols(1) = dtBranchUser.Columns("branchcode")
 
            ChildCols(0) = dtBranchDept.Columns("userid")
            ChildCols(1) = dtBranchDept.Columns("branchcode")
 
            MyDataRelation = New DataRelation("BrUserDept", ParentCols, ChildCols)
 
            dsUserDept.Relations.Add(MyDataRelation)
    
End Sub

But I got an error message when I run it:

Object reference not set to an instance of an object

What could be wrong?

Thanks in advance.

[Lunatic3]

Its because of the way you declared the array of columns. You can not say for example:

Dim X() as Integer
X(0)=10

I think that's because 'Dim x() as Integer' does not allocate memory for x(). You have to redim.