Hi Terry,
I've downloaded the code sample and performed some tests on my local side.
Based on my test , I can correctly use the Custom DropDownColumn both
statically or dynamnically. One thing need to pay attention is that since
the when we add column programmatically, we need to add it in every page
request (not only the intial time). Also, it's better that we add such
intialize code in the Page's Init event. Below is my test page's code, you
can refer to it and test on your side:
========aspx=============
<%@ Page Language="vb" AutoEventWireup="false"
Codebehind="SimpleTestPage.aspx.vb" Inherits="VBNETWebApp.SimpleTestPage"%>
<%@ Register TagPrefix="cdc" Namespace="VBNETWebApp.MyCustomColumn"
Assembly="VBNETWebApp" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<title>SimpleTestPage</title>
<meta name="GENERATOR" content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" content="Visual Basic .NET 7.1">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema"
content="
http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
<table width="80%">
<tr>
<td>Statically add columns:<br>
<asp
ataGrid id="dgStatic" runat="server"
AutoGenerateColumns="False">
<Columns>
<asp:EditCommandColumn ButtonType="LinkButton" UpdateText="Update"
CancelText="Cancel" EditText="Edit"></asp:EditCommandColumn>
<asp:BoundColumn DataField="id" HeaderText="Id"></asp:BoundColumn>
<asp:BoundColumn DataField="name"
HeaderText="Name"></asp:BoundColumn>
<cdc
ropDownColumn DataField="priority" HeaderText="Priority"/>
</Columns>
</asp
ataGrid>
</td>
</tr>
<tr>
<td>
</td>
</tr>
<tr>
<td>Dynamically add columns:<br>
<asp
ataGrid id="dgDynamic" runat="server"
AutoGenerateColumns="False">
<Columns>
<asp:EditCommandColumn ButtonType="LinkButton" UpdateText="Update"
CancelText="Cancel" EditText="Edit"></asp:EditCommandColumn>
</Columns>
</asp
ataGrid>
</td>
</tr>
</table>
</form>
</body>
</HTML>
======code behind========
Public Class SimpleTestPage
Inherits System.Web.UI.Page
#Region " Web Form Designer Generated Code "
'This call is required by the Web Form Designer.
<System.Diagnostics.DebuggerStepThrough()> Private Sub
InitializeComponent()
End Sub
Protected WithEvents dgStatic As System.Web.UI.WebControls.DataGrid
Protected WithEvents dgDynamic As System.Web.UI.WebControls.DataGrid
'NOTE: The following placeholder declaration is required by the Web
Form Designer.
'Do not delete or move it.
Private designerPlaceholderDeclaration As System.Object
Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Init
'CODEGEN: This method call is required by the Web Form Designer
'Do not modify it using the code editor.
InitializeComponent()
Init_Dynamic_Columns()
End Sub
#End Region
Private Sub Init_Dynamic_Columns()
Dim col1 As New BoundColumn
col1.DataField = "id"
col1.HeaderText = "Id"
Dim col2 As New BoundColumn
col2.DataField = "name"
col2.HeaderText = "Name"
Dim col3 As New MyCustomColumn.DropDownColumn
col3.DataSource = New String() {"top", "mid", "bot"}
col3.DataField = "priority"
dgDynamic.Columns.Add(col1)
dgDynamic.Columns.Add(col2)
dgDynamic.Columns.Add(col3)
End Sub
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
CType(dgStatic.Columns(3),
MyCustomColumn.DropDownColumn).DataSource = New String() {"top", "mid",
"bot"}
If Not IsPostBack Then
dgStatic.DataSource = GetDataSource()
dgStatic.DataBind()
dgDynamic.DataSource = GetDataSource()
dgDynamic.DataBind()
End If
End Sub
Private Function GetDataSource() As DataTable
Dim dt As New DataTable
Dim prioritys As String() = {"top", "mid", "bot"}
dt.Columns.Add("id", GetType(Long))
dt.Columns.Add("name", GetType(String))
dt.Columns.Add("priority", GetType(String))
Dim i As Int32
For i = 1 To 10
Dim dr As DataRow = dt.NewRow()
dr(0) = i
dr(1) = "Name_" & i
dr(2) = prioritys(i Mod 3)
dt.Rows.Add(dr)
Next
Return dt
End Function
Private Sub dgDynamic_EditCommand(ByVal source As Object, ByVal e As
System.Web.UI.WebControls.DataGridCommandEventArgs) Handles
dgDynamic.EditCommand
dgDynamic.EditItemIndex = e.Item.ItemIndex
dgDynamic.DataSource = GetDataSource()
dgDynamic.DataBind()
End Sub
Private Sub dgDynamic_UpdateCommand(ByVal source As Object, ByVal e As
System.Web.UI.WebControls.DataGridCommandEventArgs) Handles
dgDynamic.UpdateCommand
dgDynamic.EditItemIndex = -1
dgDynamic.DataSource = GetDataSource()
dgDynamic.DataBind()
End Sub
Private Sub dgDynamic_CancelCommand(ByVal source As Object, ByVal e As
System.Web.UI.WebControls.DataGridCommandEventArgs) Handles
dgDynamic.CancelCommand
dgDynamic.EditItemIndex = -1
dgDynamic.DataSource = GetDataSource()
dgDynamic.DataBind()
End Sub
Private Sub dgStatic_EditCommand(ByVal source As Object, ByVal e As
System.Web.UI.WebControls.DataGridCommandEventArgs) Handles
dgStatic.EditCommand
dgStatic.EditItemIndex = e.Item.ItemIndex
dgStatic.DataSource = GetDataSource()
dgStatic.DataBind()
End Sub
Private Sub dgStatic_UpdateCommand(ByVal source As Object, ByVal e As
System.Web.UI.WebControls.DataGridCommandEventArgs) Handles
dgStatic.UpdateCommand
dgStatic.EditItemIndex = -1
dgStatic.DataSource = GetDataSource()
dgStatic.DataBind()
End Sub
Private Sub dgStatic_CancelCommand(ByVal source As Object, ByVal e As
System.Web.UI.WebControls.DataGridCommandEventArgs) Handles
dgStatic.CancelCommand
dgStatic.EditItemIndex = -1
dgStatic.DataSource = GetDataSource()
dgStatic.DataBind()
End Sub
End Class
===================
Regards,
Steven Cheng
Microsoft Online Support
Get Secure!
www.microsoft.com/security
(This posting is provided "AS IS", with no warranties, and confers no
rights.)
--------------------
| Thread-Topic: DataGrid (fao Steven Cheng)
| thread-index: AcWfIxuit5hxRqK3RaCi34EZGJIKOw==
| X-WBNR-Posting-Host: 194.200.135.5
| From: "=?Utf-8?B?VGVycnkgSG9sbGFuZA==?="
<
[email protected]>
| References: <#
[email protected]>
<
[email protected]>
| Subject: RE: DataGrid (fao Steven Cheng)
| Date: Fri, 12 Aug 2005 02:49:18 -0700
| Lines: 253
| Message-ID: <
[email protected]>
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| Path: TK2MSFTNGXA01.phx.gbl!TK2MSFTNGXA03.phx.gbl
| Xref: TK2MSFTNGXA01.phx.gbl
microsoft.public.dotnet.framework.aspnet.webcontrols:10409
| X-Tomcat-NG: microsoft.public.dotnet.framework.aspnet.webcontrols
|
| My clsDropDownColumn as an exact copy of that in example.
|
| My page HTML is
| =========================================
| <%@ Register TagPrefix="uc1" TagName="ctlMaint_List"
| Src="UserControls/ctlMaint_List.ascx" %>
| <%@ Register TagPrefix="ddc" Namespace="ControlExtenders"
| Assembly="ControlExtenders"%>
| <%@ Page Language="vb" AutoEventWireup="false"
Codebehind="pgeTest.aspx.vb"
| Inherits="CSAWeb.pgeTest"%>
| <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
| <HTML>
| <HEAD>
| <title>pgeTest</title>
| <meta name="GENERATOR" content="Microsoft Visual Studio .NET 7.1">
| <meta name="CODE_LANGUAGE" content="Visual Basic .NET 7.1">
| <meta name="vs_defaultClientScript" content="JavaScript">
| <meta name="vs_targetSchema"
| content="
http://schemas.microsoft.com/intellisense/ie5">
| <LINK href="Styles.css" type="text/css" rel="stylesheet">
| </HEAD>
| <body MS_POSITIONING="FlowLayout">
| <form id="Form1" method="post" runat="server">
| <P>
| <asp
ataGrid id="DataGrid1" runat="server"
AutoGenerateColumns="False">
| <Columns>
| <asp:BoundColumn DataField="ID"></asp:BoundColumn>
| <asp:BoundColumn DataField="username"></asp:BoundColumn>
| <ddc:clsDropDownColumn DataField="UstyID" HeaderText="User Type"/>
| </Columns>
| </asp
ataGrid></P>
| <P> </P>
| <P> </P>
| </form>
| </body>
| </HTML>
| =========================================
|
|
| My Page code is
| ==============================
| Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
| System.EventArgs) Handles MyBase.Load
| 'Put user code to initialize the page here
| DataGrid1.DataSource = clsUser_ROC.GetUser_ROC
| SetUpGrid()
| DataBind()
| 'CtlMaint_ManyToMany21.InitialiseControl()
| End Sub
| Private Sub SetUpGrid()
| Dim o As New clsDropDownColumn
|
| With o
| .DataField = "UstyID"
| .DataTextField = "Desc"
| .DataValueField = "ID"
| .HeaderText = "User Type"
| .DataSource = GetDS() ' clsUserType_NVL.GetList
| End With
| DataGrid1.Columns.Add(o)
| End Sub
| Private Function GetDS() As ArrayList
| Dim al As New ArrayList
| al.Add("Value 1")
| al.Add("Value 2")
| al.Add("Value 3")
| Return al
| End Function
| =========================================
|
| Where clsUser_ROC.GetUser_ROC returns a collection of object with the
| following public interface
| =========================================
| Public Property ID() As Integer
| Get
| Return m_intID
| End Get
|
| Set(ByVal Value As Integer)
| If m_intID <> Value Then
| m_intID = Value
| End If
| End Set
| End Property
|
| Public Property FirstName() As String
| Get
| Return m_strFirstName
| End Get
|
| Set(ByVal Value As String)
| If m_strFirstName <> Value Then
| m_strFirstName = Value
| End If
| End Set
| End Property
|
| Public Property Surname() As String
| Get
| Return m_strSurname
| End Get
|
| Set(ByVal Value As String)
| If m_strSurname <> Value Then
| m_strSurname = Value
| End If
| End Set
| End Property
|
| Public Property Email() As String
| Get
| Return m_strEmail
| End Get
|
| Set(ByVal Value As String)
| If m_strEmail <> Value Then
| m_strEmail = Value
| End If
| End Set
| End Property
|
| Public Property Username() As String
| Get
| Return m_strUsername
| End Get
|
| Set(ByVal Value As String)
| If m_strUsername <> Value Then
| m_strUsername = Value
| End If
| End Set
| End Property
|
| Public Property Password() As String
| Get
| Return m_strPassword
| End Get
|
| Set(ByVal Value As String)
| If m_strPassword <> Value Then
| m_strPassword = Value
| End If
| End Set
| End Property
|
| Public Property UstyID() As Integer
| Get
| Return m_intUstyID
| End Get
|
| Set(ByVal Value As Integer)
| If m_intUstyID <> Value Then
| m_intUstyID = Value
| End If
| End Set
| End Property
| =========================================
|
|
|
| "Steven Cheng[MSFT]" wrote:
|
| > Hi Terry,
| >
| > Thanks for your followup.
| > As for the new problem you met, do you mean that you just use the
sample
| > custom column in the MSDN atrticle and got some error to work in your
own
| > page? Have you made any modification on that column? I'll have a
further
| > look into the sample column first since I've direclty used it in my
page.
| > If there're any other findings, please feel free to post here.
| >
| > Thanks & Regards,
| >
| > Steven Cheng
| > Microsoft Online Support
| >
| > Get Secure!
www.microsoft.com/security
| > (This posting is provided "AS IS", with no warranties, and confers no
| > rights.)
| >
| >
| >
| >
| > --------------------
| > | From: "Terry Holland" <
[email protected]>
| > | Subject: DataGrid (fao Steven Cheng)
| > | Date: Wed, 10 Aug 2005 12:58:01 +0100
| > | Lines: 46
| > | X-Priority: 3
| > | X-MSMail-Priority: Normal
| > | X-Newsreader: Microsoft Outlook Express 6.00.2800.1506
| > | X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1506
| > | Message-ID: <#
[email protected]>
| > | Newsgroups: microsoft.public.dotnet.framework.aspnet.webcontrols
| > | NNTP-Posting-Host: host240.multiserv.com 194.200.135.240
| > | Path: TK2MSFTNGXA01.phx.gbl!TK2MSFTNGP08.phx.gbl!TK2MSFTNGP09.phx.gbl
| > | Xref: TK2MSFTNGXA01.phx.gbl
| > microsoft.public.dotnet.framework.aspnet.webcontrols:10377
| > | X-Tomcat-NG: microsoft.public.dotnet.framework.aspnet.webcontrols
| > |
| > | This is a follow on from a previous posting. Ive posted as new post
as
| > the
| > | previous thread seems to have dried up
| > |
| > |
| > | Steven
| > |
| > | Thank you. I mangaged to get your sample code working. However I am
| > having
| > | difficulty getting the code in the article
| > | #Creating Custom Columns for the ASP.NET Datagrid
| > |
| >
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnaspp/html
| > | /creatingcustomcolumns.asp
| > |
| > | I am able to get the example that you can download working but am
unable
| > to
| > | get it working in an application of my own.
| > |
| > | I get the following error which occurrs on the line
| > | cell.text = dgi.DataItem(DataField)
| > |
| > | error
| > | =============
| > | Line 34: Throw New Exception(ex.InnerException.ToString)
| > | Line 35: End Try
| > | Line 36: End Sub
| > |
| > |
| > | Source File:
C:\_Development\CSA\Dev\ControlExtenders\clsDropDownColumn.vb
| > | Line: 34
| > |
| > | Stack Trace:
| > |
| > |
| > | [NullReferenceException: Object reference not set to an instance of an
| > | object.]
| > |
| > | =============
| > |
| > | Any ideas why this is happening?
| > |
| > | Also, is it possible for me to add a customcolumn completely
| > | programmatically (ie without the need to add a @register directive
and a
| > | <ddg
ropDownColumn .../> tag on my page?
| > |
| > | thanks in advance
| > |
| > |
| > |
| > |
| >
| >
|
