Drop Down List Items from Codebehind

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Hello

I'm trying to construct a dropdown list in a code behind page, based on the values of a FormView.

I have most of the logic sorted (I think) to put in the correct values, but when I select an item from the drop down list, the orginial drop down list is appended with the same values again, so the list keeps growing and growing, when all I want it to do is retain the selected item and the original list content (no matter how many times the page is posted back from the drop down).

I have placed the following code in the Page_Load event section, could this be causing the problem?

Any help appreciated, but beaware, I'm a newbie in this.....

C#

DropDownList3.Items.Add("-");
if (callDetails.DataKey["SOURCE_REFERENCE"] != "")
{
    DropDownList3.Items.Add("Source");
}
if (callDetails.DataKey["SUBJECT_REFERENCE"] != "")
{
    DropDownList3.Items.Add("Subject");
}
if (callDetails.DataKey["REFERENCE"] != "")
{
    DropDownList3.Items.Add("3rd Party");
}

Posted 18-Oct-10 23:21pm

codemagpie

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Comments

Hiren solanki 19-Oct-10 6:00am

after solution provided by brij I can add or I am assuming that you may have Autopostback = 'true' with DropDownList.

2 solutions

Solution 2

Hi Brij

I used a combination of your code and something to handle if it is a postback.

Seems to do the job but there might be a slicker way.

Thanks anyway.

Cheers

Peter

C#

if (!IsPostBack)
{
    DropDownList3.Items.Add(new ListItem("-", "-"));
    if (callDetails.DataKey["SOURCE_REFERENCE"] != "")
    {
        DropDownList3.Items.Add(new ListItem("Source", callDetails.DataKey["SOURCE_REFERENCE"].ToString()));
        Label10.Text = DropDownList3.SelectedValue.ToString();
    }
    if (callDetails.DataKey["SUBJECT_REFERENCE"] != "")
    {
        DropDownList3.Items.Add(new ListItem("Subject", callDetails.DataKey["SUBJECT_REFERENCE"].ToString()));
        Label10.Text = DropDownList3.SelectedValue.ToString();
    }
    if (callDetails.DataKey["REFERENCE"] != "")
    {
        DropDownList3.Items.Add(new ListItem("3rd Party", callDetails.DataKey["REFERENCE"].ToString()));
        Label10.Text = DropDownList3.SelectedValue.ToString();
    }
}

if (IsPostBack)
{
    if (callDetails.DataKey["SOURCE_REFERENCE"] != "")
    {
        Label10.Text = DropDownList3.SelectedValue.ToString();
    }
    if (callDetails.DataKey["SUBJECT_REFERENCE"] != "")
    {
        Label10.Text = DropDownList3.SelectedValue.ToString();
    }
    if (callDetails.DataKey["REFERENCE"] != "")
    {
        Label10.Text = DropDownList3.SelectedValue.ToString();
    }
}

Posted 19-Oct-10 0:01am

codemagpie

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Brij · Accepted Answer · 2010-10-18T23:27:00

Solution 1

Put your code like

if(!IsPostBack)
{
DropDownList3.Items.Add("-");
if (callDetails.DataKey["SOURCE_REFERENCE"] != "")
{   
 DropDownList3.Items.Add("Source");
}
if (callDetails.DataKey["SUBJECT_REFERENCE"] != "")
{   
 DropDownList3.Items.Add("Subject");
}
if (callDetails.DataKey["REFERENCE"] != "")
{   
 DropDownList3.Items.Add("3rd Party");}
}
}

Now your code will not be executed more than once.

Posted 18-Oct-10 23:27pm

Brij

Comments

codemagpie 19-Oct-10 5:48am

Hi Brij

I have tried that and yes it doesn't append to the list anymore, but the selected item value is not being passed now, it is just keep the first selected item value?

Any further help would be most appreciated.

Cheers

Pete

Hiren solanki 19-Oct-10 5:59am

!IsPostBack annoys newbies much. :)

Drop Down List Items from Codebehind

2 solutions

Solution 1

Solution 2

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Drop Down List Items from Codebehind

2 solutions

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Solution 2

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