GridComboBoxCellRenderer setting the listbox items

[Administrator]

Hi,

I have derived from GridComboBoxCellRenderer and GridComboBoxCellModel to create a custom combobox cell. Now I want to fill the combobox dynamically with different items. I thought I can use the constructor of the GridComboBoxCellRenderer derived class to add the items. But this doesn't work:

public class ExampleCellRenderer : GridComboBoxCellRenderer
{
public ExampleCellRenderer(GridControlBase grid, GridCellModelBase cellModel)
: base(grid, cellModel)
{
ListBoxPart.Items.Clear();
ListBoxPart.Items.Add("ParameterValue2");
ListBoxPart.Items.Add("ParameterValue1");
}
....


Now when I click on the corresponding cell, I can't see the dropdown box with the items. Did I forgot something??

Thanks in advance,
Frank

[Administrator]

Hi Frank,

You can override GridComboBoxCellRenderer. OnShowDropDown method and fill combobox cell dynamically with different items using ListBoxPart.Items property. Here is a code snippet to show this.

public class ExampleCellRenderer : GridComboBoxCellRenderer
{
public ExampleCellRenderer(GridControlBase grid, GridCellModelBase cellModel): base(grid, cellModel)
{
this.SupportsFocusControl = true;//cancel the editing in a cell
}

protected override void OnShowDropDown()
{
ListBoxPart.Items.Clear();
ListBoxPart.Items.Add("ParameterValue2");
ListBoxPart.Items.Add("ParameterValue1");
base.OnShowDropDown ();
}
}

Best Regards,
Haneef

[Administrator]

Hi Haneef,

thanks for your sample. I have still the problem that nothing happens when I click on the combobox dropdown button. I have attached a sample where you can see the strange behavior. Just click on the "EnumValue2" cell.

Appendix:
It is currently implemented that the combobox button is only visible when the user clicks on the corresponding cell.

Thanks in advance

SyncfusionCustomCell.zip

[Administrator]

Hi Frank,

To show the dropdown button only for the current cell, you need to set the ShowButtons property to GridShowButtons.ShowCurrentCell. Here is a modified code snippet to show this.

void gridGroupingControl1_QueryCellStyleInfo(object sender, Syncfusion.Windows.Forms.Grid.Grouping.GridTableCellStyleInfoEventArgs e)
{
Element eDisplayElement = e.TableCellIdentity.DisplayElement;
if (eDisplayElement.Kind == DisplayElementKind.Record && eDisplayElement.ParentTable != null)
{
if (e.TableCellIdentity.Column != null && e.TableCellIdentity.Column.Name == "ObjectParameter")
{
GridRecordRow rec = e.TableCellIdentity.Table.DisplayElements[e.TableCellIdentity.RowIndex] as GridRecordRow;
if (rec != null)
{
MyData dr = rec.GetData() as MyData;
if (dr.ObjectParameter.GetType() == typeof(EnumParameter))
{
e.Style.CellType = "CustomCell";
e.Style.ShowButtons = Syncfusion.Windows.Forms.Grid.GridShowButtons.ShowCurrentCell;
}
}

}
}

Here is a modified sample.
http://www.syncfusion.com/Support/user/uploads/SyncfusionCustomCell_9455b56e.zip

Best Regards,
Haneef