Question

我需要将GroupBox绑定到BindingSource，而public class CustomerType { public int Id {get; set;} public string Name {get; set;} public MemberType MemberType {get; set;} } public enum MemberType {Adult, Child}又绑定到以下对象：

groupBoxMemberType.DataBindings.Add("Selected", this.bindingSource, "MemberType");

我遵循了answer to create a custom GroupBox。我还设置了数据绑定如下：

customerType = customerTypeRequest.Load(id);
bindingSource.DataSource = customerType;  //raises exception

但是，在加载现有对象时，我得到以下异常：

DataBinding在列表中找不到适合所有绑定的行。

设置数据源时发生异常：

BindingSource

我错过了什么？是否有替代方法可以将单选按钮绑定到数据源，特别是{{1}}？

Answer 1

这是更改后的代码：

[DefaultBindingProperty("Selected")]
public class RadioGroupBox : GroupBox
{
    #region events

    [Description("Occurs when the selected value changes.")]
    public event SelectedChangedEventHandler SelectedChanged;

    public class SelectedChangedEventArgs : EventArgs
    {
        public int Selected { get; private set; }

        internal SelectedChangedEventArgs(int selected)
        {
            this.Selected = selected;
        }
    }
    public delegate void SelectedChangedEventHandler(object sender, SelectedChangedEventArgs e);

    #endregion

    private int selected;

    [Browsable(false)]
    [Bindable(BindableSupport.Yes, BindingDirection.TwoWay)]
    [Description("The selected value associated with this control."), Category("Data")]
    public int Selected
    {
        get { return selected; }
        set
        {
            int val = 0;
            var radioButton = this.Controls.OfType<RadioButton>()
                .FirstOrDefault(radio =>
                    radio.Tag != null
                   && int.TryParse(radio.Tag.ToString(), out val) && val == value);

            if (radioButton != null)
            {
                radioButton.Checked = true;
                selected = val;
            }
        }
    }

    protected override void OnControlAdded(ControlEventArgs e)
    {
        base.OnControlAdded(e);

        var radioButton = e.Control as RadioButton;
        if (radioButton != null)
            radioButton.CheckedChanged += radioButton_CheckedChanged;
    }

    protected void OnSelectedChanged(SelectedChangedEventArgs e)
    {
        if (SelectedChanged != null)
            SelectedChanged(this, e);
    }

    private void radioButton_CheckedChanged(object sender, EventArgs e)
    {
        var radio = (RadioButton)sender;
        int val = 0;
        if (radio.Checked && radio.Tag != null
             && int.TryParse(radio.Tag.ToString(), out val))
        {
            selected = val;
            OnSelectedChanged(new SelectedChangedEventArgs(selected));
        }
    }
}

除了将Tag属性设置为枚举的相应int值之外，还需要在表单中订阅SelectedChanged事件，例如：

private void radioGroupBoxMemberType_SelectedChanged(object sender, SelectedChangedEventArgs e)
{
    customerType.MemberType = (MemberType)e.Selected;
}

此课程的改进将是：

从RadioButton继承并使用新属性而不是Tag属性。
直接在控件中访问并设置bindingsource属性，以避免订阅该事件。

自定义组框未绑定到bindingsource

1 个答案: