asked on

C#, ASP How to check how many check boxes are checked

Hello,
We have a web page with dynamically loaded check boxes (depends on how many records in database).
What i need is to make sure the user checks only 5 check boxes. And if he checks the 6th one, give him a message that he can only check 5.
ASP:

Please select up to five:
<asp:Repeater runat="server" ID="rptCandidats" >
        <ItemTemplate>
             <div>
                 <asp:checkbox id="chResponse" runat="server"  AutoPostBack="True"   OnCheckedChanged="Check_Clicked"></asp:checkbox>
<%# Eval("ResText")%> <a href="<%#Eval("ResLink")%>" class="moreinfo">   More Info</a>
                 <asp:HiddenField ID="ResId" runat="server" Value ='<%#Eval("ResponId")%>' />                           </div>
       </ItemTemplate>
</asp:Repeater>

Open in new window

I tried to use OnCheckedChanged event, but it doesn't work.
Below is a C# code:

protected void Check_Clicked(Object sender, EventArgs e)
       {
           int checkedCount = 0;
           foreach (RepeaterItem r in rptCandidats.Items)
           {
              CheckBox cb = (CheckBox)r.FindControl("chResponse");
               if (cb.Checked)
               {
                   checkedCount += (sender as CheckBox).Checked ? 1 : -1;
               }
           }
           if (checkedCount > 5)
           {
               System.Web.HttpContext.Current.Response.Write("<SCRIPT LANGUAGE=\"JavaScript\">alert(\"Only Up to five candidates can be selected.\")</SCRIPT>");
           }

       }

Open in new window

Any ideas how can i achieve it?
Thanks.

Kyle Abrahams, PMP

Don't use response.Write.

use ScriptManager.RegisterStartupScript:
http://msdn.microsoft.com/en-us/library/bb359558%28v=vs.110%29.aspx

string javaScript = "<script language=JavaScript>\n" + "alert('Only Up to five candidates can be selected');\n" + "</script>";

ScriptManager.RegisterStartupScript(updatePanelId,updatePanelId.GetType()
, "alert", javaScript, true);

Galina Besselyanova

ASKER

Thanks!
Here is my new code

 protected void Check_Clicked(Object sender, EventArgs e)
       {
           string sysAlert="Only up to five selections.";
           int checkedCount = 0;
           foreach (RepeaterItem r in rptCandidats.Items)
           {
               CheckBox cb = (CheckBox)r.FindControl("chResponse");
               if (cb.Checked)
               {
                   checkedCount += (sender as CheckBox).Checked ? 1 : -1;
                   if (checkedCount > 5)
                   {
                      
       Page.ClientScript.RegisterStartupScript(this.GetType(), "This Alert", "alert('" + sysAlert + "');", true);
       cb.Checked = false;

                   }
               }
           }
          
       }

Open in new window

It is working, but now, when you click on the check box, the page blinking like it reloads .

Kyle Abrahams, PMP

take it out of the for each. and do you have your repeater ajaxified in an updatepanel?

protected void Check_Clicked(Object sender, EventArgs e)
       {
           string sysAlert="Only up to five selections.";
           int checkedCount = 0;
           foreach (RepeaterItem r in rptCandidats.Items)
           {
               CheckBox cb = (CheckBox)r.FindControl("chResponse");
               if (cb.Checked)
               {
                   checkedCount += cb.Checked ? 1 : 0;
                }
           }
          
        if (checkedCount > 5)
        {

       Page.ClientScript.RegisterStartupScript(this.GetType(), "This Alert", "alert('" + sysAlert + "');", true);
       cb.Checked = false;
        }

       }

Open in new window

Galina Besselyanova

ASKER

I'm sorry, i'm new to it.
There is no updatepanel.
And why remove For each if i need to count how many check boxes are already checked?
Am i doing something wrong?

ASKER CERTIFIED SOLUTION