Image in Header Problem

[Xavier Soares]

Hello,

After your previous support, I can add images to the row header.

Now I'm having some problems when I activate the group by funcionalities. For example, after spending some time analising the code, I founded that if I want to use images in the header row, I need to change ShowRowHeader =  false.

Now I'm having another problem. In same Grids, I get the error:  "Object reference not set to an instance of an object." in the GREEN row

Here Is the code that i'm using:

Dim header As GridTableHeaderRowElement = TryCast(TryCast(Me.DetailedProposals.GridElement, GridTableElement).TableBodyElement.Children(0), GridTableHeaderRowElement)

Me.DetailedProposals.ImageList = Me.ImageList1

For Each element As Telerik.WinControls.RadElement In header.Children

Select Case TryCast(element, GridHeaderCellElement).Text

Case "Molde"

TryCast(element, GridHeaderCellElement).ImageIndex = 0

TryCast(element, GridHeaderCellElement).Text = ""

Case "Print"

TryCast(element, GridHeaderCellElement).ImageIndex = 1

TryCast(element, GridHeaderCellElement).Text = ""

Case "EMail"

TryCast(element, GridHeaderCellElement).ImageIndex = 2

TryCast(element, GridHeaderCellElement).Text = ""

Case "Intranet"

TryCast(element, GridHeaderCellElement).ImageIndex = 3

TryCast(element, GridHeaderCellElement).Text = ""

End Select

element.Alignment = ContentAlignment.MiddleCenter

Next


Can you help? This code works in other radgrid and all columns have name/text

Thank You.
Luis Mauricio

[Jack]

Hello Luis Mauricio,

Thank you for contacting us.

This exception is thrown because when grouping is applied, GridTableHeaderRowElement contains indent cells. These cells can't be cast to a GridHeaderCellElement. Therefore, you should check if the cast operation returns Nothing. Consider the code snippet below:

For Each element As Telerik.WinControls.RadElement In header.Children
    Dim HeaderCell As GridHeaderCellElement = TryCast(element, GridHeaderCellElement)
        If HeaderCell IsNot Nothing Then
            Select Case HeaderCell.Text
                Case "Molde"
                HeaderCell.ImageIndex = 0
                HeaderCell.Text = ""
            Case "Print"
                HeaderCell.ImageIndex = 1
                HeaderCell.Text = ""
            Case "EMail"
                HeaderCell.ImageIndex = 2
                HeaderCell.Text = ""
            Case "Intranet"
                HeaderCell.ImageIndex = 3
                HeaderCell.Text = ""
            End Select
            element.Alignment = ContentAlignment.MiddleCenter
        End If
    Next

In our latest release we have added a ViewCellFormatting event. This event fires every time a system cell needs to change its state. Maybe, processing this event will be a better choice for this task. See the following sample:

    Private Sub ViewCellFormatting(ByVal sender As Object, ByVal e As CellFormattingEventArgs) Handles RadGridView.ViewCellFormatting
        Dim HeaderCell As GridHeaderCellElement = TryCast(e.CellElement, GridHeaderCellElement)
        If HeaderCell IsNot Nothing Then
            Select Case HeaderCell.Text
                Case "Molde"
                    HeaderCell.ImageIndex = 0
                    HeaderCell.Text = ""
                Case "Print"
                    HeaderCell.ImageIndex = 1
                    HeaderCell.Text = ""
                Case "EMail"
                    HeaderCell.ImageIndex = 2
                    HeaderCell.Text = ""
                Case "Intranet"
                    HeaderCell.ImageIndex = 3
                    HeaderCell.Text = ""
            End Select
            HeaderCell.Alignment = ContentAlignment.MiddleCenter
        End If
    End Sub

I hope this helps. Please let me know if you have other questions.

 
All the best,
Jack
the Telerik team

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