如何将组合框的选定值设置为字符串值

Question

I've spent a while looking for an answer but I haven't found anything that has worked for me so far. I have a system that saves the contents of a combobox to a database. When I get the contents back from the database, I'm trying to set the selected item of the combobox to the item returned from the database. for example: XAML:

<ComboBox SelectedValuePath="Content" x:Name="cmbMyCmb" SelectedIndex="0" SelectionChanged="cmbMyCmb_SelectionChanged">
      <ComboBoxItem Content="Please Select"/>
      <ComboBoxItem Content="Item 1"/>
      <ComboBoxItem Content="Item 2"/>
      <ComboBoxItem Content="Item 3"/>
</ComboBox>

Code Behind:

cmbMyCmb.SelectedValue = itemFromDatabase;

If I display the itemFromDatabase it shows "Item 2" and it is a string.

What I have on the form is an input form and a datagrid. When an item is selected from the datagrid I want the items to be displayed in the input form so they can be edited and updated. I have all other items displaying I just need this combobox to set the selected value to the string from the database.

Answer 1

Get rid of SelectedIndex="0" in your combo definition and try this:

 <ComboBox x:Name="cmbMyCmb" SelectedValuePath="Content" SelectionChanged="cmbMyCmb_SelectionChanged" Margin="99,104,117.4,157.8">
        <ComboBoxItem Content="Please Select"/>
        <ComboBoxItem Content="Item 1"/>
        <ComboBoxItem Content="Item 2"/>
        <ComboBoxItem Content="Item 3"/>
    </ComboBox>

Code behind:

private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        //get item from database here
        string itemFromDatabase = "Item 2";

        cmbMyCmb.SelectedValue = itemFromDatabase;
    }

Note I'm doing it in the Loaded event as a sample on how to change. If you do it in SelectionChanged event, the result is that whatever the user selects, your code behind is going to put it back to whatever value you want, which doesn't make sense.