Datagridview column running total

I need sample code for the following example:

Col1 Col2

1. 123| 123
2. 123| 246
3. 123| 369
4. 123| 492

I want to keep a running total of Col1 values in Col2.
Row 1 Col2 to show Col1 cell 1 value
Row 2 Col2 to show sum of Col1 cells 1 & 2.
Row 3 Col2 to show sum of Col2 cells 1 & 2 & 3
Row 4 Col2 to show sum of Col2 cells 1 & 2 & 3 & 4

Column 1 is databound - Column 2 can be databound or unbound...

Thanks!

Visual Basic.NET.NET Programming

Last Comment

dave_sky

8/22/2022 - Mon

Jesus Rodriguez

12/24/2013

.
Dim Sum as Double=0
For I as Integer=0 to Tbl.Rows.Count-1
Sum+=Tbl.Rows(I).Item("COL1")
Tbl.Rows(I).BeginEdit
Tbl.Rows(I).Item("COL2")=Sum
Tbl.Rows(I).EndEdit()
Tbl.AcceptChanges()
Next I

YourGrid.Datasource=Tbl

dave_sky

12/24/2013

ASKER

I tried this and get an "Object reference not set to an instance of an object".error at TblBreakeven in: For I As Integer = 0 To TblBreakEven.Rows.Count - 1

Private Sub btnTotal_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnTotal.Click

        Dim tblbreakeven As DataTable
        Dim Sum As Double = 0
        For I As Integer = 0 To TblBreakEven.Rows.Count - 1
            Sum += tblbreakeven.Rows(I).Item("COL1")
            TblBreakEven.Rows(I).BeginEdit()
            TblBreakEven.Rows(I).Item("COL2") = Sum
            TblBreakEven.Rows(I).EndEdit()
            TblBreakEven.AcceptChanges()
        Next I

        TblBreakEvenDataGridView.DataSource = TblBreakEven
end Sub