GridView Checkbox Column
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04-07-2019 - |
Question
I used to have a class in 1.1 for the Datagrid that inherited from the DataGridColumn class. This allowed me to create a check box column with a client-side un/check-all box in the header. Then as I designed my grid I would just add my custom column.
I am currently on a project where I need similar functionality for the grid view, however, there does not seem to be a way to inherit or add functionality to a column.
So my question is, Is there a way to override a column? or Does this code already exist, in a reusable way?
Needs are simple: I would like for it to just register the JavaScript on the page and render a column of check boxes.
I have come across the 4guys sample already, but they have just put all the code into the code behind, I am looking for something a little less copy/paste.
Solution 3
I inherited the BoundField and came up with this:
Page Code:
<%@ register tagprefix="CAC" namespace="UI.Controls" assembly="UI.Controls" %>
<asp:gridview id="grdPrint" runat="server" autogeneratecolumns="False">
<columns>
<cac:checkallcolumn />
<asp:boundfield datafield="CompanyName" headertext="Company Name" />
</columns>
</asp:gridview>
And this is the control:
Imports system.Web.UI
Imports system.Web.UI.WebControls
Public Class CheckAllColumn
Inherits BoundField
Public Sub New()
MyBase.New()
End Sub
Public ReadOnly Property SelectedIndexes() As List(Of Int32)
Get
Dim selectedIndexList As New List(Of Int32)
Dim grdParent As GridView = CType(Me.Control, GridView)
For Each item As GridViewRow In grdParent.Rows
Dim chkBox As CheckBox = CType(item.FindControl("checkboxCol"), CheckBox)
If ((Not (chkBox) Is Nothing) _
AndAlso chkBox.Checked) Then
selectedIndexList.Add(item.DataItemIndex)
End If
Next
Return selectedIndexList
End Get
End Property
Public ReadOnly Property SelectedDataKeys() As Object()
Get
Dim dataKeyList As ArrayList = New ArrayList
Dim grdParent As GridView = CType(Me.Control, GridView)
If (grdParent.DataKeys.Count > 0) Then
For Each selectedIndex As Int32 In SelectedIndexes
Dim DataKey As Object = grdParent.DataKeys(selectedIndex).ToString
dataKeyList.Add(DataKey)
Next
End If
Return CType(dataKeyList.ToArray(GetType(System.Object)), Object())
End Get
End Property
Public Overrides Sub InitializeCell(ByVal cell As DataControlFieldCell, ByVal cellType As DataControlCellType, ByVal rowState As DataControlRowState, ByVal rowIndex As Integer)
If cell Is Nothing Then
Throw New ArgumentNullException("cell", "cell is null.")
End If
MyBase.InitializeCell(cell, cellType, rowState, rowIndex)
If (cellType = DataControlCellType.Header) OrElse (cellType = DataControlCellType.DataCell) Then
Dim checkbox As CheckBox = New CheckBox
If cellType = DataControlCellType.Header Then
checkbox.ID = "checkboxHead"
Else
checkbox.ID = "checkboxCol"
End If
cell.Controls.Add(checkbox)
End If
End Sub
Public Shared Sub RegisterClientCheckEvents(ByVal pg As Page, ByVal formID As String)
If pg Is Nothing Then
Throw New ArgumentNullException("pg", "pg is null.")
End If
If formID Is Nothing OrElse formID.Length = 0 Then
Throw New ArgumentException("formID is null or empty.", "formID")
End If
Dim strCol As String = GetCheckColScript()
Dim strHead As String = GetCheckHeadScript()
If Not pg.ClientScript.IsClientScriptBlockRegistered("clientScriptCheckAll") Then
pg.ClientScript.RegisterClientScriptBlock(pg.GetType, "clientScriptCheckAll", strHead.Replace("[frmID]", formID))
End If
If Not pg.ClientScript.IsClientScriptBlockRegistered("clientScriptCheckChanged") Then
pg.ClientScript.RegisterClientScriptBlock(pg.GetType, "clientScriptCheckChanged", strCol.Replace("[frmID]", formID))
End If
RegisterAttributes(pg)
End Sub
Private Shared Sub RegisterAttributes(ByVal ctrl As Control)
For Each wc As Control In ctrl.Controls
If wc.HasControls Then
RegisterAttributes(wc)
End If
If TypeOf (wc) Is CheckBox Then
Dim chk As CheckBox = DirectCast(wc, CheckBox)
If Not chk Is Nothing AndAlso chk.ID = "checkboxCol" Then
chk.Attributes.Add("onclick", "CheckChanged()")
ElseIf Not chk Is Nothing AndAlso chk.ID = "checkboxHead" Then
chk.Attributes.Add("onclick", "CheckAll(this)")
End If
End If
Next
End Sub
Private Shared Function GetCheckColScript() As String
Dim strScript As String
strScript = " <script language=JavaScript>"
strScript &= " function CheckAll( checkAllBox )"
strScript &= " {"
strScript &= " var frm = document.[frmID];"
strScript &= " var ChkState=checkAllBox.checked;"
strScript &= " for(i=0;i< frm.length;i++)"
strScript &= " {"
strScript &= " e=frm.elements[i];"
strScript &= " if(e.type=='checkbox' && e.name.indexOf('checkboxCol') != -1)"
strScript &= " e.checked= ChkState ;"
strScript &= " }"
strScript &= " }"
strScript &= " </script>"
Return strScript
End Function
Private Shared Function GetCheckHeadScript() As String
Dim strScript As String
strScript = "<script language=JavaScript>"
strScript &= "function CheckChanged()"
strScript &= "{"
strScript &= " var frm = document.[frmID];"
strScript &= " var boolAllChecked;"
strScript &= " boolAllChecked=true;"
strScript &= " for(i=0;i< frm.length;i++)"
strScript &= " {"
strScript &= " e=frm.elements[i];"
strScript &= " if ( e.type=='checkbox' && e.name.indexOf('checkboxCol') != -1 )"
strScript &= " if(e.checked== false)"
strScript &= " {"
strScript &= " boolAllChecked=false;"
strScript &= " break;"
strScript &= " }"
strScript &= " }"
strScript &= " for(i=0;i< frm.length;i++)"
strScript &= " {"
strScript &= " e=frm.elements[i];"
strScript &= " if ( e.type=='checkbox' && e.name.indexOf('checkboxHead') != -1 )"
strScript &= " {"
strScript &= " if( boolAllChecked==false)"
strScript &= " e.checked= false ;"
strScript &= " else"
strScript &= " e.checked= true;"
strScript &= " break;"
strScript &= " }"
strScript &= " }"
strScript &= " }"
strScript &= " </script>"
Return strScript
End Function
End Class
OTHER TIPS
I derived classes from System.Web.UI.WebControls.BoundField and .HyperLinkField You might be interested in inheriting from CheckBoxField class http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.checkboxfield.aspx
Could you just use a TemplateColumn with an ItemTemplate containing your CheckBox in your DataGrid Columns?
Something like:
<asp:DataGrid id="DG1" runat = "server" DataKeyField = "ID">
<Columns>
<asp:TemplateColumn HeaderText="ProductName">
<ItemTemplate>
<asp:CheckBox id="chkBox1" runat="server"
Text =<%# DataBinder.Eval(Container.DataItem,"yourDataToBind") %>
checked='<%# DataBinder.Eval(Container.DataItem,"yourBoolToBind") %>'>
</asp:CheckBox>
</ItemTemplate>
</asp:TemplateColumn>
</Columns>
</asp:DataGrid>