Cfrgtkky

I like to have a filter for a table. That's why I have a dropdown list and when I press the button filter it should change the table. After pressing the button, I come to the method btnFilter_Click. When I try to get the selected value from the dropdown list, I get the defaut value (the last inserted value in the Dropdown list) and not the one I've selected before.

HTML:

<div class="col-sm-9">

         <asp:DropDownList runat="server" ID="ddlYearForProject" CssClass="form-control">

         </asp:DropDownList>

</div>

C#:

Page_Load:

if(!IsPostback){

    if (ddlYearForProject.Items.Count == 0)

                    {

                        ddlYearForProject.Items.Insert(0, new ListItem(DateTime.Today.AddYears(-3).Year.ToString(), string.Empty));

                        ddlYearForProject.Items.Insert(0, new ListItem(DateTime.Today.AddYears(-2).Year.ToString(), string.Empty));

                        ddlYearForProject.Items.Insert(0, new ListItem(DateTime.Today.AddYears(-1).Year.ToString(), string.Empty));

                        ddlYearForProject.Items.Insert(0, new ListItem(DateTime.Today.Year.ToString(), string.Empty));

                    }

}

btnFilter_Click:

stringYear = ddlYearForProject.SelectedItem.Text;

I also tried to get the value in the page_Load, but there the selected value is the default value too.

Your problem is in the string.empty all your values will be empty and this is what the dropdown uses to identify the selected item.

Change

ddlYearForProject.Items.Insert(0, new ListItem(DateTime.Today.AddYears(-1).Year.ToString(), string.Empty));

to

ddlYearForProject.Items.Insert(0, new ListItem(DateTime.Today.AddYears(-1).Year.ToString(), DateTime.Today.AddYears(-1).Year.ToString()));

This will give the text and value to the dropdown. Or you can use an other unique value like an int or so. But if it is the same for multiple items it will not work like you expect.

Make this update in the Page Load.

if (!IsPostBack)

{

    if (ddlYearForProject.Items.Count == 0)

            {

                ddlYearForProject.Items.Insert(0, new ListItem(DateTime.Today.AddYears(-3).Year.ToString(), string.Empty));

                ddlYearForProject.Items.Insert(0, new ListItem(DateTime.Today.AddYears(-2).Year.ToString(), string.Empty));

                ddlYearForProject.Items.Insert(0, new ListItem(DateTime.Today.AddYears(-1).Year.ToString(), string.Empty));

                ddlYearForProject.Items.Insert(0, new ListItem(DateTime.Today.Year.ToString(), string.Empty));

            }

}