Why can''t you group columns that have been frozen?

[David Mecteaux]

Is there a way to allow columns that are frozen to be grouped? If not why is that the case?

[Jisha Joy]

Hi David,

With the FrozenColumn setting in GridGroupingControl, grouping by that frozen column cannot be achieved. However this can be achieved by handling FreezeRange() method call. Here is the code for your reference.

field = this.gridGroupingControl1.TableDescriptor.NameToField("SNo");
col = this.gridGroupingControl1.TableDescriptor.FieldToColIndex(field);
this.gridGroupingControl1.TableModel.Cols.FreezeRange(col,col+2);

With this code, you can set the column with name "SNo" and two subsequent columns as frozen columns.

While handling the grouping, the column index get changed based on the groupedcolumns count. Hence to retain these columns as frozen, the PropertyChanged event can be handled while grouping occurs and the freeze range can be retained accordingly with the following code in it.

if (e.PropertyName == "TableDescriptor")
{
Syncfusion.Grouping.DescriptorPropertyChangedEventArgs prop = e.Inner as Syncfusion.Grouping.DescriptorPropertyChangedEventArgs;
if (prop.PropertyName == "GroupedColumns")
{
this.gridGroupingControl1.TableModel.Cols.RestoreFrozen();
field = this.gridGroupingControl1.TableDescriptor.NameToField('SNo');
col = this.gridGroupingControl1.TableDescriptor.FieldToColIndex(field);
this.gridGroupingControl1.TableModel.Cols.FreezeRange(1, col+2);
}
}


Please refer to the sample in the following link in which this has been implemented.
http://www.syncfusion.com/uploads/redirect.aspx?&team=support&file=I717961512226581.zip

Regards,
Jisha

[David Mecteaux]

Thanks that code works.
I do have one concern about it though. Its very slow when you group columns that are frozen. It is much slower than if I wasn't using that code. Is there anyway around this?

[David Mecteaux]

Actually I have one more issue with this other than it sometimes being very slow. How can I prevent the user from dragging a frozen column to another column? I would like for the user not to be able to move any of these frozen columns.

[Jisha Joy]

Hi David,


Please try handling the following code snippet to disable dragging of frozen columns. This has been achieved by handling the TableControlQueryAllowDragColumn event.


this.gridGroupingControl1.TableControlQueryAllowDragColumn += new Syncfusion.Windows.Forms.Grid.Grouping.GridQueryAllowDragColumnEventHandler(gridGroupingControl1_TableControlQueryAllowDragColumn);

void gridGroupingControl1_TableControlQueryAllowDragColumn(object sender, Syncfusion.Windows.Forms.Grid.Grouping.GridQueryAllowDragColumnEventArgs e)
{
string colName = e.TableControl.TableDescriptor.FrozenColumn;
int colIndex = e.TableControl.TableDescriptor.Columns.IndexOf(colName);
int frozenColIndex = e.TableControl.TableDescriptor.Columns.IndexOf(e.Column);
if (frozenColIndex <= colIndex)
e.AllowDrag = false;

else
e.Handled = true;

}

Please refer the modified sample that allows us to drag drop frozen columns without any performance hit.

Regards,
Jisha



Sample11_6a0ebb6a.zip