All geek questions in one place

OnSelectedIndexChanged popup does not work

The event OnSelectedIndexChangeddoes not fire for my drop-down list. All the forums I looked at told me to add AutoPostBack="true", but that did not change the results.

HTML:

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
      <asp:Label ID="Label1" runat="server" Text="Current Time:  " /><br />
      <asp:Label ID="lblCurrent" runat="server" Text="Label" /><br /><br />
      <asp:DropDownList ID="cboSelectedLocation" runat="server" AutoPostBack="true" OnSelectedIndexChanged="cboSelectedLocation_SelectedIndexChanged"  /><br /><br />
      <asp:Label ID="lblSelectedTime" runat="server" Text="Label" />
    </div>
    </form>
</body>
</html>

Code behind:

public partial class _Default : Page 
{
    string _sLocation = string.Empty;
    string _sCurrentLoc = string.Empty;
    TimeSpan _tsSelectedTime;

    protected void Page_Load(object sender, EventArgs e)
    {
      AddTimeZones();
      cboSelectedLocation.Focus();
      lblCurrent.Text = "Currently in " + _sCurrentLoc + Environment.NewLine + DateTime.Now;
      lblSelectedTime.Text = _sLocation + ":" + Environment.NewLine + DateTime.UtcNow.Add(_tsSelectedTime);
    }

    //adds all timezone displaynames to combobox
    //defaults combo location to seoul, South Korea
    //defaults current location to current location
    private void AddTimeZones()
    {
      foreach(TimeZoneInfo tz in System.TimeZoneInfo.GetSystemTimeZones())
      {
        string s = tz.DisplayName;
        cboSelectedLocation.Items.Add(s);
        if (tz.StandardName  == "Korea Standard Time") cboSelectedLocation.Text = s;
        if (tz.StandardName == System.TimeZone.CurrentTimeZone.StandardName) _sCurrentLoc = tz.StandardName;
      }
    }

    //changes timezone name and time depending on what is selected in the cbobox.
    protected void cboSelectedLocation_SelectedIndexChanged(object sender, EventArgs e)
    {
      foreach (TimeZoneInfo tz in System.TimeZoneInfo.GetSystemTimeZones())
      {
        if (cboSelectedLocation.Text == tz.DisplayName)
        {
          _sLocation = tz.StandardName;
          _tsSelectedTime = tz.GetUtcOffset(DateTime.UtcNow);
        }
      }
    }
}

Any tips on what to look for asp coder beginners?

EDIT : added more code

Graham Clark was right in need !Page.IsPostBack, but now it's something with the global variables that I set. This code has been dragged and dropped from a C # project, so I assume there are some problems with global variables and asp.net. It is time to do more research on this subject to understand how global variables differ in an autonomous rather than a web program.
+3
1

? , , , - , .

, Page_Load. :

protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        // bind drop-down list here
    }
}
+9

Source: https://habr.com/ru/post/1749041/

More articles:


All Articles