winforms动态组合框默认值

Question

Okay, so I have a two combo boxes, one filled with modifiers (ctrl, alt, shift, windows key) and the other one with keys (AZ, F1-F12). I want to change the default value of those combo boxes to the one saved in the "Properties.Settings.Default.*", only somehow it's not working.

Here is the code that fills the combo boxes:

private void Settings_Load(object sender, EventArgs e)
{
    KeyModifiers[] modifierArray = new KeyModifiers[] { KeyModifiers.Alt, KeyModifiers.Control, 
                                                        KeyModifiers.Shift, KeyModifiers.Windows };

    var dataSourceModifiers = new List<KeyModifiers>();

    foreach(KeyModifiers modifier in modifierArray )
    {
        dataSourceModifiers.Add(modifier);
    }

    this.comboboxClickerModifier.DataSource = dataSourceModifiers;

    Keys[] keysArray = new Keys[] { Keys.A, Keys.B, Keys.C, Keys.D, Keys.E, Keys.F, Keys.G, Keys.H, Keys.I, Keys.J, Keys.K,
                                    Keys.L, Keys.M, Keys.N, Keys.O, Keys.P, Keys.Q, Keys.R, Keys.S, Keys.T, Keys.U, Keys.V, 
                                    Keys.W, Keys.X, Keys.Y, Keys.Z, Keys.F1, Keys.F2, Keys.F1, Keys.F2, Keys.F3, Keys.F4, Keys.F5,
                                    Keys.F6, Keys.F7, Keys.F8, Keys.F9, Keys.F10, Keys.F11, Keys.F12};

    var dataSourceKeys = new List<Keys>();

    foreach (Keys key in keysArray)
    {
        dataSourceKeys.Add(key);
    }

    this.comboboxClickerKey.DataSource = dataSourceKeys;

    // Down here are the ways I tried to set the default value
    comboboxClickerKey.Text = Properties.Settings.Default.Key.ToString();
    comboboxClickerKey.SelectedIndex = comboboxClickerKey.Items.IndexOf(Properties.Settings.Default.Key);
    comboboxClickerKey.SelectedItem = Properties.Settings.Default.Key;
    comboboxClickerModifier.SelectedItem = Properties.Settings.Default.Modifier;
}

At the bottom of the code you can see the ways I've tried to set the default value, but all of them failed to do so.

The Settings:

The window on start up:

Answer 1

I would recommend to store in Properties.Settings.Default.IndexModifier and Properties.Settings.Default.IndexKey (type int ) just selected indices of corresponding ComboBox controls, like for eg:

Properties.Settings.Default.IndexKey=comboboxClickerKey.SelectedIndex;
Properties.Settings.Default.Save();

and respectively, operate with that index value to force back the ComboBox control to display the appropriate item, like:

comboboxClickerKey.SelectedIndex=Properties.Settings.Default.IndexKey

The code will be much cleaner, excluding that numerous type conversions. Also, here is a link to the article describing various ComboBox data binding technique (examples pertinent to ASP.NET could be easily adapted for WinForms app as well): http://www.codeproject.com/Tips/214418/Binding-DropDownList-to-various-data-structures .

Note : regarding your code snippet, the closest to working solution is the line:

comboboxClickerKey.Text = Properties.Settings.Default.Key.ToString();

Next 3 lines do not look right and most likely will cause the exception. It may work if you don't explicitly bind DataTextField and DataValueField ; otherwise it may fail.

Hope this may help.