Gridview Custom Hierarchy

[Markus Giera]

Dear Telerik users

I've got two questions:

1. Is it possible in "Winforms Gridview" to have a custom hierarchy as shown in the wpf example: http://demos.telerik.com/wpf/?GridView/Hierarchy/CustomHierarchy ?
or in Silverlight http://demos.telerik.com/silverlight/#GridView/Hierarchy/CustomHierarchy
I've got a list of custom objects sometimes containing a collection of objects. So I want the "+" button only to display if the objects contains subobjects.

2. If not, is it possible to hide the "+" button if a row's GetChildrows returns 0 childs? (by cellformatting?)

Greets

Markus

[Svett]

Hello Markus Giera,

RadGridView for Winforms does not support custom hierarchy (yet), but you can achieve similar behavior with the presented API of RadGridView.

You need to check that a specified row has child rows. Also, as you mentioned you need to subscribe for the ViewCellFormatting event where you can hide the plus-minus element. Finally you have to prevent from expanding rows that don't have child rows in the ChildViewExpanding event. You can use the following code snippet:

private void radGridView_ViewCellFormatting(object sender, CellFormattingEventArgs e)
{
    GridGroupExpanderCellElement cellElement = e.CellElement as GridGroupExpanderCellElement;
    GridViewDataRowInfo dataRow = e.CellElement.RowInfo as GridViewDataRowInfo;

    if (cellElement != null && dataRow != null)
    {
        bool hasChildRows = false;

        if (dataRow.Tag == null)
        {
            hasChildRows = this.HasChildRows(dataRow);
            dataRow.Tag = hasChildRows;
        }
        else
        {
            hasChildRows = (bool)dataRow.Tag;
        }

        if (hasChildRows)
        {
            cellElement.ResetValue(GridGroupExpanderCellElement.SignStyleProperty, ValueResetFlags.Local);
        }
        else
        {
            cellElement.SignStyle = GridGroupExpanderCellElement.SignStyles.Image;
        }
    }
}

private void radGridView_ChildViewExpanding(object sender, ChildViewExpandingEventArgs e)
{
    GridViewDataRowInfo dataRow = e.ParentRow;

    bool hasChildRows = false;

    if (dataRow.Tag == null)
    {
        hasChildRows = this.HasChildRows(dataRow);
    }
    else
    {
        hasChildRows = (bool)dataRow.Tag;
    }

    e.Cancel = !hasChildRows;
    dataRow.Tag = hasChildRows;
}

If you need further assistance do not hesitate to write us back.
 

All the best,
Svett
the Telerik team

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[Pixie]

What is the current way to do this? SignStyleProperty and SignStyle don't seem to exist any more.

[Ivan Petrov]

Hi Pixie,

Thank you for writing.

The cell element now contains an expander element and these properties concern this inner element. Given that the code should look like this:

private void radGridView1_ViewCellFormatting(object sender, CellFormattingEventArgs e)
{
    GridGroupExpanderCellElement cellElement = e.CellElement as GridGroupExpanderCellElement;
    GridViewDataRowInfo dataRow = e.CellElement.RowInfo as GridViewDataRowInfo;

    if (cellElement != null && dataRow != null)
    {
        bool hasChildRows = false;

        if (dataRow.Tag == null)
        {
            hasChildRows = this.HasChildRows(dataRow);
            dataRow.Tag = hasChildRows;
        }
        else
        {
            hasChildRows = (bool)dataRow.Tag;
        }

        if (hasChildRows)
        {
            cellElement.Expander.ResetValue(GridExpanderItem.SignStyleProperty, ValueResetFlags.Local);
        }
        else
        {
            cellElement.Expander.SignStyle = SignStyles.Image;
        }
    }
}

I hope this will be useful. Should you have further questions, I would be glad to help.

Greetings,
Ivan Petrov
the Telerik team