將WinForms控件綁定到ObjectA.ObjectB.Property

Question

我有一個類代表這樣的車：

public class Car
{
    public event PropertyChangedEventHandler PropertyChanged;

    private void RaisePropertyChanged([CallerMemberName] string caller = "")
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(caller));
        }
    }

    public enum Colors
    {
        LaserRed,
        GenuineGraniteMica,
        BluePearl,
        SandMicaMetallic,
        NightArmorMetallic
    }

    private string _make;
    public string Make
    {
        get { return _make; }
        set {
                _make = value;
                RaisePropertyChanged();
            }
    }

    private string _model;
    public string Model
    {
        get { return _model; }
        set {
                _model = value;
                RaisePropertyChanged();
            }
    }

    private Colors _color;
    public Colors Color
    {
        get { return _color; }
        set {
                _color = value;
                RaisePropertyChanged();
            }
    }

    public Tire FrontLeftTire = new Tire();
    public Tire FrontRightTire = new Tire();
    public Tire RearLeftTire = new Tire();
    public Tire RearRightTire = new Tire();

    public Car()
    {
        // initialization code
    }

如你所見，我的Car級有四個輪胎，輪胎類看起來像這樣：

public class Tire : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    private void RaisePropertyChanged([CallerMemberName] string caller = "")
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(caller));
        }
    }

    public enum SizeValues
    {
        [Description("17 inches")]
        SeventeenInches,
        [Description("18 inches")]
        EighteenInches,
        [Description("19 inches")]
        NineteenInches,
        [Description("20 inches")]
        TwentyInches,
    }

    private string _brand;
    public string Brand
    {
        get { return _brand; }
        set
        {
            _brand = value;
            RaisePropertyChanged();
        }
    }

    private SizeValues _size;
    public SizeValues Size
    {
        get { return _size; }
        set
        {
            _size = value;
            RaisePropertyChanged();
        }
    }

    public Tire()
    {
        // initialization code
    }

在我的WinForms UI中，我有一個與每個輪胎的Size屬性相對應的組合框（下拉列表）。 我正在嘗試將每個組合框綁定到適當輪胎的Size屬性，但我用來綁定到car對象本身的屬性的代碼不起作用。 這是我用來將組合框綁定到我汽車的Color屬性的代碼：

comboBoxCarColor.DataBindings.Add(new Binding("SelectedValue", bindingSourceForCars, "Color", true, DataSourceUpdateMode.OnPropertyChanged));
comboBoxCarColor.DataSource = new BindingSource(Utility.ConvertEnumToListOfKeyValuePairs(typeof(Car.Color)), null);
comboBoxCarColor.DisplayMember = "Value";
comboBoxCarColor.ValueMember = "Key";

這很好用。 但我認為我現在遇到的問題是，我正試圖綁定一個不是汽車直接兒童財產的財產，而是汽車輪胎中的一個屬性。 所以，這樣的事情是行不通的：

comboBoxFrontLeftTimeSize.DataBindings.Add(new Binding("SelectedValue", bindingSourceForCars, "FrontLeftTire.Size", true, DataSourceUpdateMode.OnPropertyChanged));

我認為問題出在數據成員（“FrontLeftTire.Size”），但我不確定。 我只是以錯誤的方式引用這個，還是我在這里完全弄錯了？

Answer 1

我認為有兩個問題：

1）我認為您需要將Tire對象聲明為Properties，而不是Fields：

而不是這個：

public Tire FrontLeftTire = new Tire()

嘗試將其更改為：

private Tire frontLeftTire = new Tire()

public Tire FrontLeftTire {
  get { return frontLeftTire; }
}

2）我認為你可能會遇到微軟在4.0中對需要使用BindingSource的數據成員所做的重大改變。

而不是這個：

comboBoxFrontLeftTimeSize.DataBindings.Add(
                            new Binding("SelectedValue",
                                        bindingSourceForCars,
                                        "FrontLeftTire.Size",
                                        true,
                                        DataSourceUpdateMode.OnPropertyChanged));

嘗試將其更改為：

BindingSource bs = new BindingSource(bindingSourceForCars, null);
comboBoxFrontLeftTimeSize.DataBindings.Add(
                                       "SelectedValue",
                                       bs,
                                       "FrontLeftTire.Size",
                                       true,
                                       DataSourceUpdateMode.OnPropertyChanged));