Items not being updated

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I am creating a (several) combobox at Runtime and trying to manually set a SelectedValue 'standard', but I realized that even manually setting a value that exists inside the combo nothing is selected.

I’ve already checked if the data type matches (both are long).

Below the code in which I create the combo:

ComboBox cmb = new ComboBox()
{
    DropDownStyle = ComboBoxStyle.DropDown,
    BackColor = Color.FromArgb(210, 211, 213),
    ForeColor = Color.Black,
    Location = new Point(5, y),
    Size = new Size(265, 10),
    Font = new Font("Verdana", 11f, FontStyle.Regular),
    FlatStyle = FlatStyle.Popup,
    AutoCompleteMode = AutoCompleteMode.SuggestAppend,
    AutoCompleteSource = AutoCompleteSource.ListItems,
    Tag = null
};

cmb.DataSource = null;
cmb.ValueMember = "Id";
cmb.DisplayMember = "Login";
cmb.DataSource = UsuarioDB.FindAll().Where(x => x.Id > 0).OrderBy(x => x.Login).ToList();
cmb.SelectedValue = (long)1; //Aqui estou setando manualmente o valor para testar

There are three important things to score:

  1. Debugging the code I see that property DataSource is correct with all records, however the property Items is empty;
  2. Even with the property Items empty, the combo shows the values exactly as I need (I mean, running) and when changing the selected value and try to capture by SelectedValue the value comes right.
  3. In the same form is created a combobox (this in time design), where I also serve the SelectedValue manually, but this works right.

Any idea what it might be?

c# winforms combobox

  • Instead of SelectedValue because it does not use SelectedIndex?

  • Because I need to select based on ValueMember which is the Id.

  • Just for the record, you want to select an item in the combo based on its value which is a long resulting from DataSource, correct?

  • Correct @Felipedouradinho

  • I particularly use it this way when I associate a DataSource to Combobox: cmb.SelectedIndex = cmb.Items.IndexOf(UsuarioDB.Where(x => x.Id == 1).FirstOrDefault());

  • Nah, the problem doesn’t have to do with it. By the way, do you make an appointment at the bank just to validate it? It seems unnecessary.

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1 answer

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Try it like this: 

cmb.SelectedIndex = 1;

Or if you want to fill in from a value:

int index = cmb.FindString("valor");
cmb.SelectedIndex = index;

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