Controls in the Grid View Header

[Sasmita]

Hi ,

I have a Grid, I want to put a check box in the Grid Header.

I mean let's say Header Displays ID, Name and address.
Then fourth column should be something like one Checkbox followed by HeaderText Location . If not check box then any kind button control will also do.

Is there a way i can do it.
 
Thanks,
Sasmita

[Jack]

Hello Sasmita,

Thank you for contacting us.

Yes, this can be done by using custom cells. You should process the CreateRow event and create custom header row containing custom cell elements. Consider the following code snippet:

void radGridView1_CreateRow(object sender, GridViewCreateRowEventArgs e)
{
    if (e.RowInfo is GridViewTableHeaderRowInfo)
    {
        e.RowType = typeof(MyHeaderRow);
    }
}
public class MyHeaderRow : GridTableHeaderRowElement
{
    protected override GridCellElement CreateCell(GridViewColumn column)
    {
        GridViewDataColumn dataColumn = column as GridViewDataColumn;
        if (dataColumn != null && dataColumn.FieldName == "Name")
        {
            return new MyHeaderCell(column, this);
        }
        return base.CreateCell(column);
    }
}

public class MyHeaderCell : GridHeaderCellElement
{
    private RadCheckBoxElement checkbox;

    public MyHeaderCell(GridViewColumn column, GridRowElement row)
        : base(column, row)
    {
    }

    protected override void CreateChildElements()
    {
        base.CreateChildElements();

        this.checkbox = new RadCheckBoxElement();
        this.checkbox.ToggleStateChanged += new StateChangedEventHandler(checkbox_ToggleStateChanged);
        this.Children.Add(checkbox);
        ApplyThemeToElement(checkbox, "ControlDefault");
    }

    void checkbox_ToggleStateChanged(object sender, StateChangedEventArgs args)
    {
        MessageBox.Show("Checkbox state changed!");
    }

    protected override SizeF ArrangeOverride(SizeF finalSize)
    {
        SizeF size = base.ArrangeOverride(finalSize);
        this.checkbox.Arrange(new RectangleF(new PointF(4f,
            (finalSize.Height - this.checkbox.DesiredSize.Height) / 2f), this.checkbox.DesiredSize));
        return size;
    }

    private void ApplyThemeToElement(RadElement item, string themeName)
    {
        DefaultStyleBuilder builder = ThemeResolutionService.GetStyleSheetBuilder(item.ElementTree.ComponentTreeHandler,
            item.GetThemeEffectiveType().FullName, string.Empty, themeName) as DefaultStyleBuilder;
        if (builder != null)
        {
            item.Style = new XmlStyleSheet(builder.Style).GetStyleSheet();
        }
    }
}

As a last step you should eventually modify the theme. This is necessary if the cell style is registered for element type instead of class name. This is true for the default Vista theme. I have attached a modified version of that theme.

I hope this helps. Do not hesitate to write me if you have other questions.

All the best,
Jack
the Telerik team

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[Garima Mehta]

Hi, I followed all steps mentioned in above post to add check box in header row of grid. Everything is fine except theme. Function ApplyThemeToElementis not working, I am getting error because item.ElementTree is null so i am not able to fetch ComponentTreeHandler. Can you please help?

[Martin Vasilev]

Hi Garima Mehta,

In the latest version Q3 2009 SP1 we changed life cycle of the RadElements and that is why ElementTree still is not initialized when the ApplyThemeToElement has been called. To resolve this, you have to override Initialize method and call ApplyThemeToElement there, but not in CreateChildElements method:

public override void Initialize()
{
    base.Initialize();
    ApplyThemeToElement(_checkbox, "ControlDefault");
}

I hope this helps. Do not hesitate to contact us again if you have any additional questions.

Sincerely yours,
Martin Vasilev
the Telerik team

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