Updating a table from a Form DGV - vb.net

Question

I have a DGV which loads from a stored procedure in my application:
Dim conn As New SqlConnection(My.Resources.FCLRptConn)
Dim cmd As New SqlCommand("spFCLEditAgentAssignments", conn)
cmd.CommandType = CommandType.StoredProcedure
Dim ds As New DataSet
Dim DA As New SqlDataAdapter(cmd)
cmd.Parameters.AddWithValue("#ActiveIndicator", Me.tscmbActiveIndicator.ComboBox.SelectedValue)
DA.Fill(ds)
Me.dgvAgentAssignment.DataSource = ds.Tables(0)
Before this I added a DataGridViewComboBox column that binds to one of the columns in the DGV:
Dim conn As New SqlConnection(My.Resources.FCLRptConn)
Dim cmd As New SqlCommand("spFCLLUVTeamAssignment", conn)
Dim da As New SqlDataAdapter(cmd)
Dim TeamAssign As New DataTable
da.Fill(TeamAssign)
With FCLTeam
.DataPropertyName = "FCLTeamID"
.Name = "FCLTeamID"
.DataSource = TeamAssign
.DisplayMember = "FCLTeamName"
.ValueMember = "FCLTeamID"
.AutoSizeMode = DataGridViewAutoSizeColumnsMode.DisplayedCells
End With
When the table is loaded I come up with an
"Object reference not set to an instance of an object" error. This occurs in this block of code:
cmd.CommandText = "UPDATE tblFCLAgentAssignment SET [" & ColumnName & "] = '" & _
ConvertVBBooleanToSQLBit(dgvAgentAssignment.CurrentRow.Cells(ColumnName).Value) & _
"' WHERE RefID = '" & dgvAgentAssignment.CurrentRow.Cells("RefID").Value & "'"
The above code is used to update fields or cells that are updated through the DGV.
After I skip past the error I can updated the 'FCLTeamID' field with no issues. What could I be doing wrong on load?

Answer 1

If Not String.IsNullOrEmpty(ColumnName) Then
cmd.CommandText = "UPDATE tblFCLAgentAssignment SET [" & ColumnName & "] = '" & _
ConvertVBBooleanToSQLBit(dgvAgentAssignment.CurrentRow.Cells(ColumnName).Value) & _
"' WHERE RefID = '" & dgvAgentAssignment.CurrentRow.Cells("RefID").Value & "'"
End If
This took care of the ColumnName issue where if it was empty it would not try to update the table