datagridview rows are zero after leaving form

Question

For context, I have an app that does draft picks for our baseball fantasy league. It records the picks as people make them. I want to add a form with a blank grid that fills in with the picks as they are made and output to my TV. In my main form I have this simple code:

Private Sub SetUpPickBoard()

    Dim frmPickBoard As New frmResults
    frmPickBoard.Show()

End Sub

Then, in my form load for frmResults, I manually build a datagridview like such:

Private Sub frmResults_Load(sender As Object, e As EventArgs) Handles Me.Load

    Dim rsPlayers As DataTable
    Dim strSQL = "SELECT ID,DrafterName FROM tblDrafters ORDER BY DraftOrder"
    rsPlayers = frmMain.DataAccess.GetDataTable(strSQL)
    intDrafterCount = rsPlayers.Rows.Count
    For intDrafters = 0 To intDrafterCount - 1
        dgvPickBoard.Columns.Add("Drafter" & intDrafters.ToString, rsPlayers.Rows(intDrafters).Item("DrafterName"))
    Next
    For intCtr = 0 To 22
        Dim dgrNewRow As New DataGridViewRow
        dgrNewRow.HeaderCell.Value = (intCtr + 1).ToString
        dgvPickBoard.Rows.Add(dgrNewRow)
    Next
    Me.WindowState = FormWindowState.Maximized
    MsgBox(dgvPickBoard.Rows.Count & "-" & dgvPickBoard.Columns.Count)
End Sub

The msgbox at the end displays (correctly) 23-10

Then it returns to the main form. Then, in the code for making a pick, I simply tried to change the text of one of the cells in that form with the picked name.

rsResults.datagridview1.rows(rownumber).cells(columnnumber).value=strPickedName

I get index out range error. The rowcount is now 0, as is the columns. Even if I call a function in the frmResults form and pass in the row,column and text values, the datagridview still has zero rows/columns. I don't want to have to rebuild a whole grid from the DB every time I make a pick if possible.

So why is my datagridview 'empty'? It is still displayed in the form. Did I lose the reference to the rows when it left the load function?

Answer 1

I had issues with another form I was trying to manipulate, and I finally stumbled on the issue. The answer is detailed here. Basically, referencing a form by the form name essentially gives you a 'copy' of sorts of your actual form. I changed the reference of the form from frmResults to the object I created when I instanced the form of frmPickBoard (I had to move the definition to a global level, of course). I was then able to access and manipulate all controls in the form I created.

Answer 2

One problem could be, when you click on the header cell of the row, you get the ColumnIndex of -1.

Following code, catches that error and ignores it else it takes the header text of the column.

I used a different class for the sql query and i filled a DataTable with it, that is better to handle

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load

    Dim strSQL = "SELECT ID,DrafterName FROM tblDrafters ORDER BY ID"
    SQL.ExedQuey(strSQL)
    If SQL.HasException(True) Then Return
    intDrafterCount = SQL.recordCount
    For intDrafters = 0 To intDrafterCount - 1
        dgvPickBoard.Columns.Add("Drafter" & intDrafters.ToString, SQL.DBDT.Rows(intDrafters).Item("DrafterName"))
    Next
    For intCtr = 0 To 22
        Dim dgrNewRow As New DataGridViewRow
        dgrNewRow.HeaderCell.Value = (intCtr + 1).ToString
        dgvPickBoard.Rows.Add(dgrNewRow)
    Next
    Me.WindowState = FormWindowState.Maximized
    MsgBox(dgvPickBoard.Rows.Count & "-" & dgvPickBoard.Columns.Count)
End Sub

Private Sub dgvPickBoard_CellClick(sender As Object, e As DataGridViewCellEventArgs) Handles dgvPickBoard.CellClick
    If e.ColumnIndex = -1 Then
        'Headercell clicked ignore
    Else
        dgvPickBoard.Rows(e.RowIndex).Cells(e.ColumnIndex).Value = dgvPickBoard.Columns(e.ColumnIndex).HeaderText
    End If
End Sub