How to drag and drop rows or moving rows by single click on the row header in GridDataBoundGrid ?
In a GridDataBoundGrid, the grid just displays the rows as they are presented to it by the underlying datasource. You cannot easily re-order rows (and maintain this order) in a sorted DataView, as the DataView wants to immediately re-sort things as soon as some change messes up the sort order. So, if you want to move the position of the rows currently, you have to do so by moving them in the underlying datasource.
One way of doing it is add an extra DataColumn to your DataTable that holds a sortKey that reflects where you want the rows to be and use that column to always maintain a particular sort order. You don't display this column (you can hide using GridBoundColumn for the columns you want to see, or you can just hide it in the grid as the sample does). When you initially set the DataSource to the grid, you sort the datatable on this column using its defaultview.sort property. Then when you want to move rows, all you have to do is to move the sortKey values and the rows will rearrange themselves (as they must maintain the sort order).
Once you have some kind of support for maintaining arbitrary row orders in GridDataBoundGrid,the you can handle the mouse events to catch the MouseDown header and to manage the UI part of moving the rows.
The attached sample shows how you can implement a row moving routine that allows you to mouse down on the row header, and then just drag it (i.e By single click on the row header, and then to drag it). It uses cursors to give feedback during the move.
Steps for drag and drop a row:
1.Move the mouse pointer to any row header
2.Single Click on the row header (now you see a OLE Drag and Drop mouse curosr)
3.Move the row to the target
C#
public class DragRowHeaderGrid : GridDataBoundGrid
{
public DragRowHeaderGrid()
{
this.AllowDrop= false;
this.AllowSelection &= ~GridSelectionFlags.Row;
this.SortBehavior = GridSortBehavior.SingleClick;
}
protected override void OnMouseUp(System.Windows.Forms.MouseEventArgs e)
{
if(inRowMove)
{
if(targetRow > 0 && targetCol == 0 && sourceRow > 0)
{
int dir = sourceRow > targetRow ? -1 : 1;
int gridRow = this.CurrentCell.RowIndex;
int tableRow = this.Binder.RowIndexToPosition(gridRow);
CurrencyManager cm = (CurrencyManager)this.BindingContext[this.DataSource, this.DataMember];
this.BeginUpdate();
for(int i = sourceRow; i != targetRow; i += dir)
{
if(tableRow + dir < cm.Count && tableRow < cm.Count && tableRow + dir > -1 && tableRow > -1)
{
DataRowView drv1 = (DataRowView) cm.List[tableRow+ dir];
int val1 = (int) drv1.Row["sortKey"];
DataRowView drv2 = (DataRowView) cm.List[tableRow];
int val2 = (int) drv2.Row["sortKey"];
drv1.Row["sortKey"] = val2;
drv2.Row["sortKey"] = val1;
}
tableRow += dir;
}
this.CurrentCell.MoveTo(targetRow,1);
this.EndUpdate();
this.Refresh();
}
inRowMove = false;
}
base.OnMouseUp(e);
}
VB
Public Class DragRowHeaderGrid : Inherits GridDataBoundGrid
Public Sub New()
Me.AllowDrop= False
Me.AllowSelection = Me.AllowSelection And Not GridSelectionFlags.Row
Me.SortBehavior = GridSortBehavior.SingleClick
End Sub
Protected Overrides Sub OnMouseUp(ByVal e As System.Windows.Forms.MouseEventArgs)
If inRowMove Then
If targetRow > 0 AndAlso targetCol = 0 AndAlso sourceRow > 0 Then
Dim dir As Integer
If sourceRow > targetRow Then
dir = -1
Else
dir = 1
End If
Dim gridRow As Integer = Me.CurrentCell.RowIndex
Dim tableRow As Integer = Me.Binder.RowIndexToPosition(gridRow)
Dim cm As CurrencyManager = CType(Me.BindingContext(Me.DataSource, Me.DataMember), CurrencyManager)
Me.BeginUpdate()
Dim i As Integer = sourceRow
Do While i <> targetRow
If tableRow + dir < cm.Count AndAlso tableRow < cm.Count AndAlso tableRow + dir > -1 AndAlso tableRow > -1 Then
Dim drv1 As DataRowView = CType(cm.List(tableRow+ dir), DataRowView)
Dim val1 As Integer = CInt(drv1.Row("sortKey"))
Dim drv2 As DataRowView = CType(cm.List(tableRow), DataRowView)
Dim val2 As Integer = CInt(drv2.Row("sortKey"))
drv1.Row("sortKey") = val2
drv2.Row("sortKey") = val1
End If
tableRow += dir
i += dir
Loop
Me.CurrentCell.MoveTo(targetRow,1)
Me.EndUpdate()
Me.Refresh()
End If
inRowMove = False
End If
MyBase.OnMouseUp(e)
End Sub
Here is the link with both CS and VB samples: http://websamples.syncfusion.com/samples/KB/Grid.Windows/GDBG_Drag/main.htm