“Check all” functionality in group rows

AUTHOR: Desislava Yordanova

DATE MODIFIED : October 20, 2017

DATE POSTED: October 02, 2017

Problem

By default, the group rows in RadGridView display the group value and the added aggregates to the GroupDescriptor. A common scenario is to check/uncheck all rows from a certain group by a check box placed in the group header.

Solution

1. We will create a derivative of GridGroupContentCellElement and insert a RadCheckBoxElement in the cell’s children. For the correct layout of the group row element, the text will be visualized in a LightVisualElement next to the check box. Both of the elements will be hosted in StackLayoutElement. When the check box is toggled, all rows that belong to the group should be updated.

   [C#] 

   public class CustomGridGroupContentCellElement : GridGroupContentCellElement

   {

       RadCheckBoxElement checkBoxElement = new RadCheckBoxElement();

       LightVisualElement textElement = new LightVisualElement();

       StackLayoutElement stack = new StackLayoutElement();

    

       public CustomGridGroupContentCellElement(GridViewColumn column, GridRowElement row)

           : base(column, row)

       {

       }

    

       protected override Type ThemeEffectiveType

       {

           get

           {

               return typeof(GridGroupContentCellElement);

           }

       }

    

       protected override void CreateChildElements()

       {

           base.CreateChildElements();

           stack = new StackLayoutElement();

           stack.Orientation = Orientation.Horizontal;

           stack.StretchHorizontally = true;

    

           checkBoxElement.StretchHorizontally = false;

           checkBoxElement.CheckStateChanged += checkBoxElement_CheckStateChanged;

           textElement.TextAlignment = ContentAlignment.MiddleLeft;

           this.Children.Add(stack);

           stack.Children.Add(checkBoxElement);

           stack.Children.Add(textElement);

       }

    

       private void checkBoxElement_CheckStateChanged(object sender, EventArgs e)

       {

           //update child rows

           GridViewGroupRowInfo group = this.RowInfo as GridViewGroupRowInfo;

           group.Tag = checkBoxElement.Checked;

           this.GridViewElement.GridControl.BeginUpdate();

           int scrollValue = this.GridControl.TableElement.VScrollBar.Value;

           foreach (GridViewRowInfo row in this.RowInfo.ChildRows)

           {

               GridViewGroupRowInfo groupRow = row as GridViewGroupRowInfo;

               if (groupRow != null)

               {

                   Toggle(groupRow, checkBoxElement.Checked);

               }

    

               row.Cells["Discontinued"].Value = checkBoxElement.Checked;

           }

           this.GridViewElement.GridControl.EndUpdate();

           this.GridViewElement.GridControl.TableElement.VScrollBar.Value = scrollValue;

       }

    

       private void Toggle(GridViewGroupRowInfo groupRow, bool state)

       {

           groupRow.Tag = state;

           foreach (GridViewRowInfo row in groupRow.ChildRows)

           {

               GridViewGroupRowInfo g = row as GridViewGroupRowInfo;

               if (g != null)

               {

                   Toggle(g, state);

               }

    

               row.Cells["Discontinued"].Value = state;

           }

       }

    

       public override void SetContent()

       {

           base.SetContent();

           this.DrawText = false;

           textElement.Text = ((GridViewGroupRowInfo)this.RowInfo).HeaderText;

           checkBoxElement.CheckStateChanged -= checkBoxElement_CheckStateChanged;

           if (this.RowInfo.Tag != null)

           {

               checkBoxElement.Checked = (bool)this.RowInfo.Tag;

           }

           else

           {

               checkBoxElement.Checked = false;

           }

           checkBoxElement.CheckStateChanged += checkBoxElement_CheckStateChanged;

       }

   }

   [VB] 

   Public Class CustomGridGroupContentCellElement

       Inherits GridGroupContentCellElement

       Private checkBoxElement As RadCheckBoxElement

       Private textElement As LightVisualElement

       Private stack As StackLayoutElement

    

       Public Sub New(column As GridViewColumn, row As GridRowElement)

           MyBase.New(column, row)

       End Sub

    

       Protected Overrides ReadOnly Property ThemeEffectiveType() As Type

           Get

               Return GetType(GridGroupContentCellElement)

           End Get

       End Property

    

       Protected Overrides Sub CreateChildElements()

           MyBase.CreateChildElements()

           checkBoxElement = New RadCheckBoxElement()

           textElement = New LightVisualElement()

           stack = New StackLayoutElement()

           stack.Orientation = Orientation.Horizontal

           stack.StretchHorizontally = True

    

           checkBoxElement.StretchHorizontally = False

           AddHandler checkBoxElement.CheckStateChanged, AddressOf checkBoxElement_CheckStateChanged

           textElement.TextAlignment = ContentAlignment.MiddleLeft

           Me.Children.Add(stack)

           stack.Children.Add(checkBoxElement)

           stack.Children.Add(textElement)

       End Sub

    

       Private Sub checkBoxElement_CheckStateChanged(sender As Object, e As EventArgs)

           'update child rows

           Dim group As GridViewGroupRowInfo = TryCast(Me.RowInfo, GridViewGroupRowInfo)

           group.Tag = checkBoxElement.Checked

           Me.GridViewElement.GridControl.BeginUpdate()

           Dim scrollValue As Integer = Me.GridControl.TableElement.VScrollBar.Value

           For Each row As GridViewRowInfo In Me.RowInfo.ChildRows

               Dim groupRow As GridViewGroupRowInfo = TryCast(row, GridViewGroupRowInfo)

               If groupRow IsNot Nothing Then

                   Toggle(groupRow, checkBoxElement.Checked)

               End If

    

               row.Cells("Discontinued").Value = checkBoxElement.Checked

           Next

           Me.GridViewElement.GridControl.EndUpdate()

           Me.GridViewElement.GridControl.TableElement.VScrollBar.Value = scrollValue

       End Sub

    

       Private Sub Toggle(groupRow As GridViewGroupRowInfo, state As Boolean)

           groupRow.Tag = state

           For Each row As GridViewRowInfo In groupRow.ChildRows

               Dim g As GridViewGroupRowInfo = TryCast(row, GridViewGroupRowInfo)

               If g IsNot Nothing Then

                   Toggle(g, state)

               End If

    

               row.Cells("Discontinued").Value = state

           Next

       End Sub

    

       Public Overrides Sub SetContent()

           MyBase.SetContent()

           Me.DrawText = False

           textElement.Text = DirectCast(Me.RowInfo, GridViewGroupRowInfo).HeaderText

           RemoveHandler checkBoxElement.CheckStateChanged, AddressOf checkBoxElement_CheckStateChanged

           If Me.RowInfo.Tag IsNot Nothing Then

               checkBoxElement.Checked = CBool(Me.RowInfo.Tag)

           Else

               checkBoxElement.Checked = False

           End If

           AddHandler checkBoxElement.CheckStateChanged, AddressOf checkBoxElement_CheckStateChanged

       End Sub

   End Class
2. In order to replace the default group cell with the custom one, it is necessary to subscribe to the CreateCell event:

   [C#] 

   private void radGridView1_CreateCell(object sender, Telerik.WinControls.UI.GridViewCreateCellEventArgs e)

   {

       if (e.CellType == typeof(GridGroupContentCellElement))

       {

           e.CellElement = new CustomGridGroupContentCellElement(e.Column, e.Row);

       }

   }

   [VB] 

   Private Sub radGridView1_CreateCell(sender As Object, e As Telerik.WinControls.UI.GridViewCreateCellEventArgs)

       If e.CellType Is GetType(GridGroupContentCellElement) Then

           e.CellElement = New CustomGridGroupContentCellElement(e.Column, e.Row)

       End If

   End Sub
3. When a cell’s value is changed in the GridViewCheckBoxColumn the group row’s check box should be updated as well:

   [C#] 

   private void radGridView1_CellValueChanged(object sender, GridViewCellEventArgs e)

   {

       if (e.Column.Name == "Discontinued")

       {

           GridViewGroupRowInfo parentGroup = e.Row.Parent as GridViewGroupRowInfo;

           if (parentGroup != null)

           {

               bool atLeastOneOff = false;

               foreach (GridViewRowInfo row in parentGroup.ChildRows)

               {

                   if ((bool)row.Cells["Discontinued"].Value == false)

                   {

                       atLeastOneOff = true;

                       break;

                   }

               }

               parentGroup.Tag = !atLeastOneOff;

           }

       }

   }

   [VB] 

   Private Sub radGridView1_CellValueChanged(sender As Object, e As GridViewCellEventArgs)

       If e.Column.Name = "Discontinued" Then

           Dim parentGroup As GridViewGroupRowInfo = TryCast(e.Row.Parent, GridViewGroupRowInfo)

           If parentGroup IsNot Nothing Then

               Dim atLeastOneOff As Boolean = False

               For Each row As GridViewRowInfo In parentGroup.ChildRows

                   If CBool(row.Cells("Discontinued").Value) = False Then

                       atLeastOneOff = True

                       Exit For

                   End If

               Next

               parentGroup.Tag = Not atLeastOneOff

           End If

       End If

   End Sub

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