如何使用MVVM使用访问填充组合框

Question

I'm new to C# and I'm trying to create a code using MVVM pattern, but I don't know how to populate a combobox using that pattern. Please Give me help to create the ViewModel and the binding to the xaml.

Code Model:

 public int Cd_Raca
    {
        get;
        set
        {
            if(Cd_Raca != value)
            {
                Cd_Raca = value;
                    RaisePropertyChanged("Cd_Raca");
            }
        }
    }

    public string Nm_Raca
    {
        get;
        set
        {
            if(Nm_Raca != value)
            {
                Nm_Raca = value;
                    RaisePropertyChanged("Nm_Raca");
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    private void RaisePropertyChanged(string property)
    {
        if(PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(property));
        }
    }
}

Xaml:

<ComboBox x:Name="dsCmbRaca" HorizontalAlignment="Left" Margin="438,4,0,0"
                             VerticalAlignment="Top" Width="94" Height="19"/>

Answer 1

Use the ItemsSource Property and set it to an enumeration of objects. With DisplayMemberPath you can set it to a property of a single object of your list if the list is not just a list of strings.
Ie in my sample the object of the list has a Description property for display and a Value property for the selected value.

All bindings in the sample need to be a property in your ViewModel (=DataContext).

<ComboBox DisplayMemberPath="Description" HorizontalAlignment="Left" 
                  VerticalAlignment="Top" Width="120"
                  ItemsSource="{Binding myList}"
                  SelectedValue="{Binding mySelectedValue}" SelectedValuePath="Value" />  

Edit:
The List property could look like this:

    public IList<MyObject> myList { get { return new List<MyObject>();} }

The Object could look like this for example:

public class MyObject
{
    public string Description { get; }
    public enum Value { get;}
}

The Object is optional. You could just pass a list of strings.

Disclaimer: I hacked this in notepad. I hope it compiles.

UPDATE
Looking at your code at least from what you post your properties are not implemented correctly. You need a backing field if you code it like you have:

private int _cd_Raca;
private string _nm_Raca;

public int Cd_Raca
    {
        get{ return _cd_Raca;}
        set
        {
            if(_cd_Raca != value)
            {
                _cd_Raca = value;
                    RaisePropertyChanged("Cd_Raca");
            }
        }
    }

    public string Nm_Raca
    {
        get{return _nm_Raca;}
        set
        {
            if(_nm_Raca != value)
            {
                _nm_Raca = value;
                    RaisePropertyChanged("Nm_Raca");
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    private void RaisePropertyChanged(string property)
    {
        if(PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(property));
        }
    }

Reading your comment to my first answer seems you might have a specific use case. So if this update does not help maybe you can add some more information to your question.