Changing the image button on PostBack

Aker · May 19th, 2008, 09:40 AM

Hi,

I have a image button. I want that after I press that button, the image button to change. I don't know how to do that. Either from aspx file, or aspx.cs file it's ok ..

Any idea ?

Thanks

Thank you

samjudson · May 19th, 2008, 09:48 AM

I don't see what the problem is - you simply change the ImageUrl in the click event:

Code:

private void ImageButton1_Click(object sender, EventArgs e)
{
    ImageButton1.ImageUrl = "image2.gif";
}

/- Sam Judson : Wrox Technical Editor -/

Aker · May 19th, 2008, 10:05 AM

Sorry, I'm just a beginner in C# and .NET technologies.

The problem is that I have a gridView ItemTemplate field. If I'll add a OnClick function and put the code which you wrote here, it will give me the following error...Object reference not set to an instance of an object.

Thank you

samjudson · May 19th, 2008, 10:08 AM

OK, that explains your problem a little better. Try this instead then:

Code:

private void ImageButton1_Click(object sender, EventArgs e)
{
    ImageButton button = (ImageButton)sender;
    button.ImageUrl = "image2.gif";
}

/- Sam Judson : Wrox Technical Editor -/

Aker · May 19th, 2008, 10:30 AM

Well, I put that in the code but it's not working.

So I have one user list(grid View). After I'll press the ImageButton, and after he'll update the status of the user from active to inactive , I want the image button changed. the rest of the code(command name, argument and the rest) are working just fine (in sql tabel the user status is updated when I press the image button). The only thing is that the image doesn't change.

So ..some code :
aspx:
<asp:TemplateField>
<ItemTemplate>
<asp:ImageButton ID="imgbtnSetInactiveUser" runat="server" ImageUrl="~/Images/interziss.jpg" CommandName="SetInactiveUser" OnClientClick="changeImageButton" />
  </ItemTemplate>
  </asp:TemplateField>

C# :
  protected void gvUserList_RowCommand(object sender, GridViewCommandEventArgs e)
        {

            if (e.CommandName.Equals("EditUser"))
            {
                Response.Redirect("~/AddUser.aspx?UserID="+e.CommandArgument);
            }

            else if (e.CommandName.Equals("SetInactiveUser"))
            {
                Logins objLogins = new Logins();
                objLogins.SetInactiveUser(int.Parse(e.CommandArgum ent.ToString()));

            }
        }

protected void gvUserList_RowDataBound(object sender, GridViewRowEventArgs e)
        {

            LinkButton lnkUserName;
            ImageButton imgbtnSetInactiveUser;

            if (e.Row.RowType != DataControlRowType.DataRow)
            {

                return;

            }
            else
            {
                lnkUserName = (LinkButton)(e.Row.Cells[0].FindControl("lnkUserName"));
                imgbtnSetInactiveUser = (ImageButton)(e.Row.Cells[0].FindControl("imgbtnSetInactiveUser"));
                DataRowView objDRV = ((DataRowView)e.Row.DataItem);

                if (lnkUserName != null)
                {
                    lnkUserName.CommandArgument = objDRV["UserID"].ToString();
                }

                if (imgbtnSetInactiveUser != null)
                {
                    imgbtnSetInactiveUser.CommandArgument = objDRV["UserID"].ToString();
                }

            }

        }

        private void changeImageButton(object sender, EventArgs e)
        {
            ImageButton imgbtnSetInactiveUser = (ImageButton)sender;
            imgbtnSetInactiveUser.ImageUrl = "inter.jpg";
        }

Thank you

samjudson · May 19th, 2008, 10:36 AM

ClientClick is for javascript on the client side, and probably not what you want.

However you already have the code in front of you that you need.

ImageButton imgbtnSetInactiveUser;
imgbtnSetInactiveUser = (ImageButton)(e.Row.Cells[0].FindControl("imgbtnSetInactiveUser"));
imgbtnSetInactiveUser.ImageUrl = "inter.jpg";

/- Sam Judson : Wrox Technical Editor -/

Aker · May 19th, 2008, 11:20 AM

Thank you for your time and sorry for confusing you.

Thank you