C# ASP.net ImageButton click event problems

Collapse
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • dperren
    New Member
    • Mar 2007
    • 10
    #1

    C# ASP.net ImageButton click event problems

    At current, I have a set of dynamically generated image buttons, which are created with this (excert) of code:

    Code:
    TableCell tasks = new TableCell();

while (reader.Read())
                {
                    ImageButton button = new ImageButton();
		    button.Click += new System.Web.UI.ImageClickEventHandler(taskButton_Click);
                    button.ImageUrl = "Images/task.gif";
                    button.BorderWidth = 2;

                    //Assign the id to the button so we can access it in the onClick method.
                    //Best way?
                    int id = reader.GetInt32(taskID);
                    button.CommandName = id.ToString();

					bool cancelled = reader.GetBoolean(taskCancelled);
					bool complete = reader.GetBoolean(taskComplete);
					string due = reader.GetString(dueTime);

					string assignee = "";
					if(reader.IsDBNull(taskAssignee))
					{
						assignee = null;
					}
					else
					{
						assignee = reader.GetString(taskAssignee);
					}

					//Get CSS Class
					button.CssClass = this.getTaskCSS(cancelled, complete, assignee, due);

					tasks.Controls.Add(button);
                }

    This method works absolutely fine on the initial page load:
    Code:
    protected void Page_Load(object sender, EventArgs e)
    {
		string[] userSplit = HttpContext.Current.User.Identity.Name.Split(new Char[] { '\\' });
		this.user = userSplit[1];

		if (!Page.IsPostBack)
		{
			//Build list of tasks per half hour, and list of user-assigned tasks.
			this.buildTaskList();
			this.buildUserTaskList();
			this.assignDefaults();
		}
    }
    However, if I actually click one of the buttons, the click method:
    Code:
    protected void taskButton_Click(object sender, ImageClickEventArgs e)
	{
		ImageButton clicked = (ImageButton)sender;
		string taskID = clicked.CommandName;

		int id = Int32.Parse(taskID);
		this.currentTask = id;

		//taskList.Rows.Clear();
		//userTaskTable.Rows.Clear();

		this.buildTask(id);
		this.buildTaskList();
		this.buildUserTaskList();
	}
    Is never accessed: if I step through the code, it hits the IsPostBack switch, skips the contents (as expected), then finishes without ever touching the click method.

    However, if I comment out the IsPostBack switch, then the buttons function as expected, accessing the click method fine. I can't for the life of me see what's wrong here - can anyone shed any light?

    Thanks,
    Tags: None
    • dperren
      New Member
      • Mar 2007
      • 10
      #2
      Please excuse the double post, but I created a very simplified version of the application which has exactly the same effect:

      Code:
      using System;
using System.Data;
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;

public partial class _Default : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {
		if (!Page.IsPostBack)
		{
			drawImages();
		}
    }

	protected void drawImages()
	{
		int i = 0;

		TableRow row = new TableRow();
		TableCell cell = new TableCell();

		while (i < 5)
		{
			ImageButton imbutton = new ImageButton();
		    imbutton.Click += new ImageClickEventHandler(googlePictureClick_Click);
            imbutton.ImageUrl = "http://content.answers.com/main/content/wp/en/thumb/6/69/48px-Google_Earth.png";
            imbutton.BorderWidth = 2;

			cell.Controls.Add(imbutton);
			i++;
		}

		row.Cells.Add(cell);
		Table1.Rows.Add(row);
	}

	protected void googlePictureClick_Click(object sender, ImageClickEventArgs e)
	{
		drawImages();
	}
}
      Code:
      <%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
		<asp:Table ID="Table1" runat="server">
		</asp:Table>
		&nbsp;</div>
    </form>
</body>
</html>
      It's most probably something really stupid, I'm only on my third day of this...

      Thanks again,

        Comment

        • dperren
          New Member
          • Mar 2007
          • 10
          #3
          Managed to sort it - the IsPostBack indeed shouldn't have been there; instead I cleared the tables of their rows and updated them with the new ones.

            Comment

            Previous template Next
            Working...