Several people have noted that when using a DataList whose RepeatColumns property value is 0, the DataListAdapter crashes:

• http://forums.asp.net/thread/1298246.aspx
• http://forums.asp.net/thread/1290684.aspx
• http://forums.asp.net/thread/1275928.aspx
• http://forums.asp.net/thread/1298056.aspx

I thought the authors of those threads and other forum readers might want to comment on the experimental version of an enhanced DataListAdapter that attempts to handle the case of RepeatColumns equals 0 in a manner consistent with the framework's original intent:

If this property is set to 0, the DataList control displays its items in a single row or column, based on the value of the RepeatDirection property. If the RepeatDirection property is set to RepeatDirection.Horizontal, the items are displayed in a single row. If the RepeatDirection property is set to RepeatDirection.Vertical, the items are displayed in a single column.

http://windowssdk.msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref26/html/P_System_Web_UI_WebControls_DataList_RepeatColumns.asp

If you are using version 1.1 of the kit, here is a replacement for DataListAdapter.cs (I've not created a VB version but could if it is something folks really need to see right now).  I'm interested in comments and criticism of this version.  Thanks.

 

 

---

using System;
using System.Data;
using System.Collections;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

namespace CSSFriendly
{
    public class DataListAdapter : System.Web.UI.WebControls.Adapters.WebControlAdapter
    {
        private int RepeatColumns
        {
            get
            {
                DataList dataList = Control as DataList;
                int nRet = 1;
                if (dataList != null)
                {
                    if (dataList.RepeatColumns == 0)
                    {
                        if (dataList.RepeatDirection == RepeatDirection.Horizontal)
                        {
                            nRet = dataList.Items.Count;
                        }
                    }
                    else
                    {
                        nRet = dataList.RepeatColumns;
                    }
                }
                return nRet;
            }
        }

        public DataListAdapter()
        {
        }

        /// ///////////////////////////////////////////////////////////////////////////////
        /// PROTECTED        
        
        protected override void OnInit(EventArgs e)
        {
            base.OnInit(e);
            RegisterScripts();
        }

        protected override void RenderBeginTag(HtmlTextWriter writer)
        {
            if ((Control != null) && (Control.Attributes["CssSelectorClass"] != null) && (Control.Attributes["CssSelectorClass"].Length > 0))
            {
                writer.WriteLine();
                writer.WriteBeginTag("div");
                writer.WriteAttribute("class", Control.Attributes["CssSelectorClass"]);
                writer.Write(HtmlTextWriter.TagRightChar);
                writer.Indent++;
            }

            writer.WriteLine();
            writer.WriteBeginTag("div");
            writer.WriteAttribute("class", "AspNet-DataList");
            writer.Write(HtmlTextWriter.TagRightChar);            
        }

        protected override void RenderEndTag(HtmlTextWriter writer)
        {
            writer.WriteEndTag("div");

            if ((Control != null) && (Control.Attributes["CssSelectorClass"] != null) && (Control.Attributes["CssSelectorClass"].Length > 0))
            {
                writer.Indent--;
                writer.WriteLine();
                writer.WriteEndTag("div");
            }

            writer.WriteLine();
        }

        protected override void RenderContents(HtmlTextWriter writer)
        {
            DataList dataList = Control as DataList;
            if (dataList != null)
            {
                writer.Indent++;
                writer.WriteLine();
                writer.WriteBeginTag("table");
                writer.WriteAttribute("cellpadding", "0");
                writer.WriteAttribute("cellspacing", "0");
                writer.WriteAttribute("summary", Control.ToolTip);
                writer.Write(HtmlTextWriter.TagRightChar);
                writer.Indent++;

                if (dataList.HeaderTemplate != null)
                {
                    PlaceHolder container = new PlaceHolder();
                    dataList.HeaderTemplate.InstantiateIn(container);
                    container.DataBind();

                    if ((container.Controls.Count == 1) && typeof(LiteralControl).IsInstanceOfType(container.Controls[0]))
                    {
                        writer.WriteLine();
                        writer.WriteBeginTag("caption");
                        writer.Write(HtmlTextWriter.TagRightChar);

                        LiteralControl literalControl = container.Controls[0] as LiteralControl;
                        writer.Write(literalControl.Text.Trim());

                        writer.WriteEndTag("caption");
                    }
                    else
                    {
                        writer.WriteLine();
                        writer.WriteBeginTag("thead");
                        writer.Write(HtmlTextWriter.TagRightChar);
                        writer.Indent++;

                        writer.WriteLine();
                        writer.WriteBeginTag("tr");
                        writer.Write(HtmlTextWriter.TagRightChar);
                        writer.Indent++;

                        writer.WriteLine();
                        writer.WriteBeginTag("th");
                        writer.WriteAttribute("colspan", RepeatColumns.ToString());
                        writer.Write(HtmlTextWriter.TagRightChar);
                        writer.Indent++;

                        writer.WriteLine();
                        container.RenderControl(writer);

                        writer.Indent--;
                        writer.WriteLine();
                        writer.WriteEndTag("th");

                        writer.Indent--;
                        writer.WriteLine();
                        writer.WriteEndTag("tr");

                        writer.Indent--;
                        writer.WriteLine();
                        writer.WriteEndTag("thead");
                    }
                }

                if (dataList.FooterTemplate != null)
                {
                    writer.WriteLine();
                    writer.WriteBeginTag("tfoot");
                    writer.Write(HtmlTextWriter.TagRightChar);
                    writer.Indent++;

                    writer.WriteLine();
                    writer.WriteBeginTag("tr");
                    writer.Write(HtmlTextWriter.TagRightChar);
                    writer.Indent++;

                    writer.WriteLine();
                    writer.WriteBeginTag("td");
                    writer.WriteAttribute("colspan", RepeatColumns.ToString());
                    writer.Write(HtmlTextWriter.TagRightChar);
                    writer.Indent++;

                    PlaceHolder container = new PlaceHolder();
                    dataList.FooterTemplate.InstantiateIn(container);
                    container.DataBind();
                    container.RenderControl(writer);

                    writer.Indent--;
                    writer.WriteLine();
                    writer.WriteEndTag("td");

                    writer.Indent--;
                    writer.WriteLine();
                    writer.WriteEndTag("tr");

                    writer.Indent--;
                    writer.WriteLine();
                    writer.WriteEndTag("tfoot");
                }

                if (dataList.ItemTemplate != null)
                {
                    writer.WriteLine();
                    writer.WriteBeginTag("tbody");
                    writer.Write(HtmlTextWriter.TagRightChar);
                    writer.Indent++;

                    int nItemsInColumn = (int)Math.Ceiling(((Double)dataList.Items.Count) / ((Double)RepeatColumns));
                    for (int iItem = 0; iItem < dataList.Items.Count; iItem++)
                    {
                        int nRow = iItem / RepeatColumns;
                        int nCol = iItem % RepeatColumns;
                        int nDesiredIndex = iItem;
                        if (dataList.RepeatDirection == RepeatDirection.Vertical)
                        {
                            nDesiredIndex = (nCol * nItemsInColumn) + nRow;
                        }

                        if ((iItem % RepeatColumns) == 0)
                        {
                            writer.WriteLine();
                            writer.WriteBeginTag("tr");
                            writer.Write(HtmlTextWriter.TagRightChar);
                            writer.Indent++;
                        }

                        writer.WriteLine();
                        writer.WriteBeginTag("td");
                        writer.Write(HtmlTextWriter.TagRightChar);
                        writer.Indent++;

                        foreach (Control itemCtrl in dataList.Items[iItem].Controls)
                        {
                            itemCtrl.RenderControl(writer);
                        }

                        writer.Indent--;
                        writer.WriteLine();
                        writer.WriteEndTag("td");

                        if (((iItem + 1) % RepeatColumns) == 0)
                        {
                            writer.Indent--;
                            writer.WriteLine();
                            writer.WriteEndTag("tr");
                        }
                    }

                    if ((dataList.Items.Count % RepeatColumns) != 0)
                    {
                        writer.Indent--;
                        writer.WriteLine();
                        writer.WriteEndTag("tr");
                    }

                    writer.Indent--;
                    writer.WriteLine();
                    writer.WriteEndTag("tbody");
                }

                writer.Indent--;
                writer.WriteLine();
                writer.WriteEndTag("table");

                writer.Indent--;
                writer.WriteLine();
            }
        }

        /// ///////////////////////////////////////////////////////////////////////////////
        /// PRIVATE        

        private void RegisterScripts()
        {
        }
    }
}

I tripped over the datalistadapter problem when instering a wizard, found the c# fix, used online c# to vb.net converter, and fixed up the parts that the converters just couldn't get right. Wizard control now works fine, but I haven't used it outside a test enviroment.  

Imports System
Imports System.Data
Imports System.Collections
Imports System.Configuration
Imports System.Web
Imports System.Web.Security
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts
Imports System.Web.UI.HtmlControls


Namespace CSSFriendly
    _
    Public Class DataListAdapter
        Inherits System.Web.UI.WebControls.Adapters.WebControlAdapter

        Private ReadOnly Property RepeatColumns() As Integer
            Get
                Dim dataList As DataList = Nothing
                Try
                    dataList = CType(Control, DataList)
                Catch ex As Exception
                    '

                End Try
                Dim nRet As Integer = 1
                If Not (dataList Is Nothing) Then
                    If dataList.RepeatColumns = 0 Then
                        If dataList.RepeatDirection = RepeatDirection.Horizontal Then
                            nRet = dataList.Items.Count
                        End If
                    Else
                        nRet = dataList.RepeatColumns
                    End If
                End If
                Return nRet
            End Get
        End Property


        Public Sub New()
        End Sub 'New


        '/ ///////////////////////////////////////////////////////////////////////////////
        '/ PROTECTED        

        Protected Overrides Sub OnInit(ByVal e As EventArgs)
            MyBase.OnInit(e)
            RegisterScripts()
        End Sub 'OnInit



        Protected Overrides Sub RenderBeginTag(ByVal writer As HtmlTextWriter)
            If ((Not IsNothing(Control)) AndAlso (Not IsNothing(Control.Attributes.Item("CssSelectorClass"))) AndAlso (Control.Attributes.Item("CssSelectorClass").Length > 0)) Then
                writer.WriteLine()
                writer.WriteBeginTag("div")
                writer.WriteAttribute("class", Control.Attributes("CssSelectorClass"))
                writer.Write(HtmlTextWriter.TagRightChar)
                writer.Indent = writer.Indent + 1
            End If

            writer.WriteLine()
            writer.WriteBeginTag("div")
            writer.WriteAttribute("class", "AspNet-DataList")
            writer.Write(HtmlTextWriter.TagRightChar)
        End Sub 'RenderBeginTag



        Protected Overrides Sub RenderEndTag(ByVal writer As HtmlTextWriter)
            writer.WriteEndTag("div")

            If ((Not IsNothing(Control)) AndAlso (Not IsNothing(Control.Attributes.Item("CssSelectorClass"))) AndAlso (Control.Attributes.Item("CssSelectorClass").Length > 0)) Then
                writer.Indent -= 1
                writer.WriteLine()
                writer.WriteEndTag("div")
            End If

            writer.WriteLine()
        End Sub 'RenderEndTag



        Protected Overrides Sub RenderContents(ByVal writer As HtmlTextWriter)
            Dim dataList As DataList = Nothing
            Try
                dataList = CType(Control, DataList)
            Catch ex As Exception
                '

            End Try
            If Not (dataList Is Nothing) Then
                writer.Indent += 1
                writer.WriteLine()
                writer.WriteBeginTag("table")
                writer.WriteAttribute("cellpadding", "0")
                writer.WriteAttribute("cellspacing", "0")
                writer.WriteAttribute("summary", Control.ToolTip)
                writer.Write(HtmlTextWriter.TagRightChar)
                writer.Indent += 1

                If Not (dataList.HeaderTemplate Is Nothing) Then
                    Dim container As New PlaceHolder()
                    dataList.HeaderTemplate.InstantiateIn(container)
                    container.DataBind()

                    If container.Controls.Count = 1 And GetType(LiteralControl).IsInstanceOfType(container.Controls(0)) Then
                        writer.WriteLine()
                        writer.WriteBeginTag("caption")
                        writer.Write(HtmlTextWriter.TagRightChar)

                        Dim literalControl As LiteralControl = container.Controls(0) '
                        'ToDo: Error processing original source shown below
                        '
                        '
                        '-------------------------------------------------------------------------------^--- Syntax error: ';' expected

                        writer.Write(literalControl.Text.Trim())

                        writer.WriteEndTag("caption")
                    Else
                        writer.WriteLine()
                        writer.WriteBeginTag("thead")
                        writer.Write(HtmlTextWriter.TagRightChar)
                        writer.Indent += 1

                        writer.WriteLine()
                        writer.WriteBeginTag("tr")
                        writer.Write(HtmlTextWriter.TagRightChar)
                        writer.Indent += 1

                        writer.WriteLine()
                        writer.WriteBeginTag("th")
                        writer.WriteAttribute("colspan", RepeatColumns.ToString())
                        writer.Write(HtmlTextWriter.TagRightChar)
                        writer.Indent += 1

                        writer.WriteLine()
                        container.RenderControl(writer)

                        writer.Indent -= 1
                        writer.WriteLine()
                        writer.WriteEndTag("th")

                        writer.Indent -= 1
                        writer.WriteLine()
                        writer.WriteEndTag("tr")

                        writer.Indent -= 1
                        writer.WriteLine()
                        writer.WriteEndTag("thead")
                    End If
                End If

                If Not (dataList.FooterTemplate Is Nothing) Then
                    writer.WriteLine()
                    writer.WriteBeginTag("tfoot")
                    writer.Write(HtmlTextWriter.TagRightChar)
                    writer.Indent += 1

                    writer.WriteLine()
                    writer.WriteBeginTag("tr")
                    writer.Write(HtmlTextWriter.TagRightChar)
                    writer.Indent += 1

                    writer.WriteLine()
                    writer.WriteBeginTag("td")
                    writer.WriteAttribute("colspan", RepeatColumns.ToString())
                    writer.Write(HtmlTextWriter.TagRightChar)
                    writer.Indent += 1

                    Dim container As New PlaceHolder()
                    dataList.FooterTemplate.InstantiateIn(container)
                    container.DataBind()
                    container.RenderControl(writer)

                    writer.Indent -= 1
                    writer.WriteLine()
                    writer.WriteEndTag("td")

                    writer.Indent -= 1
                    writer.WriteLine()
                    writer.WriteEndTag("tr")

                    writer.Indent -= 1
                    writer.WriteLine()
                    writer.WriteEndTag("tfoot")
                End If

                If Not (dataList.ItemTemplate Is Nothing) Then
                    writer.WriteLine()
                    writer.WriteBeginTag("tbody")
                    writer.Write(HtmlTextWriter.TagRightChar)
                    writer.Indent += 1

                    Dim nItemsInColumn As Integer = CInt(Math.Ceiling((CType(dataList.Items.Count, [Double]) / CType(RepeatColumns, [Double]))))
                    Dim iItem As Integer
                    For iItem = 0 To dataList.Items.Count - 1
                        Dim nRow As Integer = iItem / RepeatColumns
                        Dim nCol As Integer = iItem Mod RepeatColumns
                        Dim nDesiredIndex As Integer = iItem
                        If dataList.RepeatDirection = RepeatDirection.Vertical Then
                            nDesiredIndex = nCol * nItemsInColumn + nRow
                        End If

                        If iItem Mod RepeatColumns = 0 Then
                            writer.WriteLine()
                            writer.WriteBeginTag("tr")
                            writer.Write(HtmlTextWriter.TagRightChar)
                            writer.Indent += 1
                        End If

                        writer.WriteLine()
                        writer.WriteBeginTag("td")
                        writer.Write(HtmlTextWriter.TagRightChar)
                        writer.Indent += 1

                        Dim itemCtrl As Control
                        For Each itemCtrl In dataList.Items(iItem).Controls
                            itemCtrl.RenderControl(writer)
                        Next itemCtrl

                        writer.Indent -= 1
                        writer.WriteLine()
                        writer.WriteEndTag("td")

                        If (iItem + 1) Mod RepeatColumns = 0 Then
                            writer.Indent -= 1
                            writer.WriteLine()
                            writer.WriteEndTag("tr")
                        End If
                    Next iItem

                    If dataList.Items.Count Mod RepeatColumns <> 0 Then
                        writer.Indent -= 1
                        writer.WriteLine()
                        writer.WriteEndTag("tr")
                    End If

                    writer.Indent -= 1
                    writer.WriteLine()
                    writer.WriteEndTag("tbody")
                End If

                writer.Indent -= 1
                writer.WriteLine()
                writer.WriteEndTag("table")

                writer.Indent -= 1
                writer.WriteLine()
            End If
        End Sub 'RenderContents


        '/ ///////////////////////////////////////////////////////////////////////////////
        '/ PRIVATE        

        Private Sub RegisterScripts()
        End Sub 'RegisterScripts

    End Class 'DataListAdapter

End Namespace 'CSSFriendly

 

Line 109 should be...

Dim

LiteralControl = container.Controls(0)

I ONLY used it on the Wizard, so I'm going to bet that it probably won't work on a real datalist.

Did you mean line 115?

That one already is like that. I don't understand it, Webdev511.