c# programatically selecting dropdown value
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Thread: c# programatically selecting dropdown value

  1. #1
    Join Date
    Aug 2008

    Exclamation c# programatically selecting dropdown value

    I am new at C# and it seems the following code below does not seem to select my combobox value:
        private void button1_Click(object sender, EventArgs e)
           cbPortNumber.SelectedIndex = 3;
    The dropdown looks like this:

    All code above does not seem to select HDMI 4 on the list... The error i have is:

    System.ArgumentOutOfRangeException: InvalidArgument=Value of '2' is not valid for 'SelectedIndex'. Parameter name: SelectedIndex at System.Windows.Forms.ComboBox.set_SelectedIndex(Int32 value)

    Any help would be great!

    **update showing combobox**

            // cbPortNumber
            this.cbPortNumber.AutoCompleteMode = System.Windows.Forms.AutoCompleteMode.Append;
            this.cbPortNumber.Enabled = false;
            this.cbPortNumber.FormattingEnabled = true;
            this.cbPortNumber.Location = new System.Drawing.Point(174, 40);
            this.cbPortNumber.Name = "cbPortNumber";
            this.cbPortNumber.Size = new System.Drawing.Size(133, 21);
            this.cbPortNumber.TabIndex = 11;
            this.cbPortNumber.Text = "global_hdmi_port";
            this.helpPortNumber.SetToolTip(this.cbPortNumber, "The HDMI port number, to which you connected your USB-CEC adapter.");
            this.cbPortNumber.SelectedIndexChanged += new System.EventHandler(this.cbPortNumber_SelectedIndexChanged);
        #region Global settings
        public CECSettingByte HDMIPort
            if (!_settings.ContainsKey(KeyHDMIPort))
              CECSettingByte setting = new CECSettingByte(KeyHDMIPort, "HDMI port", 1, _changedHandler) { LowerLimit = 1, UpperLimit = 15, EnableSetting = EnableHDMIPortSetting };
              setting.Format += delegate(object sender, ListControlConvertEventArgs args)
                ushort tmp;
                if (ushort.TryParse((string)args.Value, out tmp))
                  args.Value = "HDMI " + args.Value;
              _settings[KeyHDMIPort] = setting;
            return _settings[KeyHDMIPort].AsSettingByte;
    And this is what fires the action after selecting something in that dropdown:
        private void OnSettingChanged(CECSetting setting, object oldValue, object newValue)
          if (setting.KeyName == CECSettings.KeyHDMIPort)
            CECSettingByte byteSetting = setting as CECSettingByte;
            if (byteSetting != null)
              if (!Settings.OverridePhysicalAddress.Value)
                Config.HDMIPort = byteSetting.Value;
              CECActions.SetConnectedDevice(Settings.ConnectedDevice.Value, byteSetting.Value);
    Last edited by StealthRT; May 11th, 2013 at 01:27 PM.

  2. #2
    Join Date
    Jan 2006
    Fox Lake, IL

    Re: c# programatically selecting dropdown value

    It's actually firing multiple times. Try the CLICK event instead

    CodeGuru Article: Bound Controls are Evil-VB6
    2013 Samples: MS CODE Samples

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    2006, 2007 & 2008 MVP Visual Basic
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