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Asked: 2026-05-24T11:08:52+00:00

I’m trying to subclass a GridView that is located in a UserControl. I want

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I’m trying to subclass a GridView that is located in a UserControl. I want to be able to handle the events in a separate page as a result of this.

Basically I have the code as follows:

My UserControl with a GridView:

<%@ Control Language="C#" AutoEventWireup="false" CodeBehind="StdList.ascx.cs" Inherits="UCS_Web.uP.UserControls.StdList" %>
<div>
<asp:Panel ID="Panel1" runat="server">

<asp:GridView ID="_gridView" runat="server" PageSize="6" 
        GridLines="None" AutoGenerateColumns="False" 
        OnRowCommand="_gridView_RowCommand" AutoGenerateEditButton="false" 
        OnDataBound="_gridView_DataBound" OnPreRender="_gridView_PreRender">

        <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
        <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" HorizontalAlign="Left" CssClass="gridViewHdr" />
        <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />

    </asp:GridView>
</asp:Panel>

A page that uses the UserControl would be like this: 

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="BypassReasonsPage.aspx.cs" Inherits="UCS_Web.uP.Tools.BypassReasonsPage" %>

<%@ Register Src="~/uP/UserControls/StdList.ascx" TagName="List" TagPrefix="uc" %>

<body>
<form id="form1" runat="server">
    <div>
        <uc:List ID="uc_list" runat="server" />
    </div>
</form>

It’s code behind:

uc_list.GridView.DataSource = this.TCW.Copy.bypassReasons;
uc_list.GridView.DataBind();

To make this page work, I include this file which sets which columns are data bound, etc.:

public class BypassReasonsByToolTable : UCS_Web.uP.UserControls.StdList.ICustomTable
{      
  public DataControlField[] Columns
  {
     get
     {
         BoundField col1 = new BoundField();
         col1.DataField = "Code";
         col1.HeaderText = "Code";
         col1.SortExpression = "Code";
         col1.ItemStyle.Width = new Unit(50, UnitType.Percentage);

         BoundField col2 = new BoundField();
         col2.DataField = "Text";
         col2.HeaderText = "Text";
         col2.SortExpression = "Text";
         col2.ItemStyle.Width = new Unit(50, UnitType.Percentage);

         TemplateField editReason = new TemplateField();
         editReason.ItemTemplate = new addTemplate();

         return new DataControlField[] { col1, col2, editReason };
     }
  }

I want to be able to have the OnRowCommand, OnRowDelete, and all event handlers in a separate file instead of being in the CodeBehind of the UserControl. How can I go about making this work?

I tried making them as virtual classes and overriding them on the pages I use them on, but that did not work. Any other methods that could make this work?

EDIT: UserControl CodeBehind

namespace UCS_Web.uP.UserControls
{
   public partial class StdList : UserControl
   {
      private ICustomTable m_custom = null;

protected void _gridView_DataBound(object sender, EventArgs e)
  {
      if (_gridView.Rows.Count > 0)
      {
          for (int i = _gridView.Rows.Count + 1; i <= _gridView.PageSize - 1; i++)
          {
              GridViewRow row = new GridViewRow(
                      0,
                      0,
                      DataControlRowType.DataRow,
                  //(i % 2 > 0) ? datacontrolrowstate.normal : datacontrolrowstate.alternate);
                      DataControlRowState.Alternate);

              foreach (DataControlField field in _gridView.Columns)
              {
                  TableCell cell = new TableCell();
                  cell.Text = "&nbsp;";
                  row.Cells.Add(cell);
              }
        //row.Attributes.Add("OnClick", "javascript:alert();");
              row.BackColor = System.Drawing.ColorTranslator.FromHtml("#ffffff");
              _gridView.Controls[0].Controls.AddAt(i, row);
          }
      }

  }

protected void _gridView_RowCommand(object sender, GridViewCommandEventArgs e)
  {

      if (e.CommandName == "Delete")
      {
          //DO MY DELETE STUFF FOR THIS SPECIFIC PAGE
      }
  }
}

EDIT: My new override function added to the .cs file (tried many variations, but this is the current)

namespace UCS_Web.uP.UserControls
{
public class MyStdList : StdList
{
    protected override void _gridView_RowCommand(object sender, GridViewCommandEventArgs e){
        Response.Redirect("HERPA DERP!");
    }
}

}

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1 Answer

  1. Editorial Team

    Your user control is partial class right?

    See C#’s partial keyword:

    It is possible to split the definition of a class or a struct, an interface or a method over two or
    more source files. Each source file contains a section of the type or
    method definition, and all parts are combined when the application is
    compiled.

    It could look like this

    // MyOtherFile.cs:

namespace MyWebSite.UserControls
{
    public partial class MyUserControl : System.Web.UI.UserControl
    {
        protected override void OnInit(System.EventArgs e)
        {
            base.OnInit(e);

            _gridView.OnRowCommand += _gridBiew_RowCommand;
            _gridView.OnDataBound += _gridView_DataBound;
        }

        // events here...
    }
}

    To override your methods in a subclass, the base class StdList needs to have virtual methods and/or properties.

    See C#’s virtual keyword:

    The virtual keyword is used to modify a method, property, indexer, or event declaration and allow
    for it to be overridden in a derived class. For example, this method
    can be overridden by any class that inherits it:

      namespace UCS_Web.uP.UserControls
  {
      public partial class StdList : UserControl
      {
          private ICustomTable m_custom = null;

      }

      protected virtual void _gridView_DataBound(object sender, EventArgs e)
      {
          if (_gridView.Rows.Count > 0)
          {
              for (int i = _gridView.Rows.Count + 1; i <= _gridView.PageSize - 1; i++)
              {
                  GridViewRow row = new GridViewRow(
                          0,
                          0,
                          DataControlRowType.DataRow,
                      //(i % 2 > 0) ? datacontrolrowstate.normal : datacontrolrowstate.alternate);
                          DataControlRowState.Alternate);

                  foreach (DataControlField field in _gridView.Columns)
                  {
                      TableCell cell = new TableCell();
                      cell.Text = "&nbsp;";
                      row.Cells.Add(cell);
                  }
            //row.Attributes.Add("OnClick", "javascript:alert();");
                  row.BackColor = System.Drawing.ColorTranslator.FromHtml("#ffffff");
                  _gridView.Controls[0].Controls.AddAt(i, row);
              }
          }
      }

      protected virtual void _gridView_RowCommand(object sender, GridViewCommandEventArgs e)
      {
              // I do nothing for now... A subclass could override me and do very nice stuff
      } 
  }

    And…

      namespace UCS_Web.uP.UserControls
  {
      public partial class SpecialStdList : StdList { }

      protected override void _gridView_RowCommand(object sender, GridViewCommandEventArgs e)
      {
          // I do very nice stuff
      } 
  }
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