c# programmable selecting dropdown value

Question

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.SelectedValue = 3;

or

   cbPortNumber.setValue("3");

or

   cbPortNumber.SelectedIndex = cbPortNumber.FindString("3");

or

   cbPortNumber.SelectedIndex = cbPortNumber.Items.IndexOf(cbPortNumber.Items.FindByValue("HDMI 4"));

}

The dropdown looks like this: enter image description here

All code above does not seem to select HDMI 4 on the list... I dont have any errors but i also don't have it being selected.

Any help would be great!

update showing combobox enter image description here

UPDATE 2

    // 
    // 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
{
  get
  {
    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;
      };

      Load(setting);
      _settings[KeyHDMIPort] = setting;
    }
    return _settings[KeyHDMIPort].AsSettingByte;
  }
}

Update 3

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);
    }
  }

Venson · Accepted Answer · 2013-05-11 01:13:03Z

1

So this code is working fine for me:

private void button1_Click(object sender, EventArgs e)
{
    comboBox1.SelectedIndex = 2;
}

you can not access a ItemSource if there are no items to access. The simple way is to Init the items over the Desinger

enter image description here

( Sory for the nonlocalized IDE ) than you can set the Property SelectedIndex to a Index that exits. The other way is to Add all HDMI items with the Combobox1.Items.Add function.

If you ever used Forms in VB ... its still the same

public Form1()
{
    InitializeComponent();

    var hdmi = "HDMI";

    for (int i = 1; i < 15; i++)
    {
        comboBox1.Items.Add( hdmi + i);
    }
}

private void button1_Click(object sender, EventArgs e)
{
    if (comboBox1.Items.Count >= 2)
        comboBox1.SelectedIndex = 2;
}

edited May 11, 2013 at 1:13

answered May 11, 2013 at 0:46

Venson

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12 Comments

Adrian Over a year ago

Adding breakpoints at the start of the event handlers will show you if/when they're being triggered.

StealthRT Over a year ago

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

Venson Over a year ago

be sure that you jusing the right combobox! set a breakpoint to the assignment and look whats inside the ItemSouce

StealthRT Over a year ago

I am using the correct combobox. See updated OP for an image.

Venson Over a year ago

How do you fill your ItemSource?

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