如何确定哪个属性是数据绑定的默认属性？

Question

Given a Class of X that has multiple properties that are bindable, how do I determine which one should be the default property to select via reflection?

In the Winforms designer you can select Databinding. How does Visual Studio determine that "EditValue" should be the default property to bind to rather than say "Text"?

I already know how to get properties and attributes from the object, but I'm missing something that would tell me which one to use as default.

Answer 1

You can rely on DefaultBindingProperty attribute of the class.

For example a DateTimePicker is decorated with [DefaultBindingProperty("Value")] but a ComboBox is decorated with [DefaultBindingProperty("Text")] .

You can create a function like following, to get name of the default binding property of a control:

public string GetDefaultBindingPropertyValue(Control c)
{
    var att = c.GetType().GetCustomAttributes(true)
        .OfType<DefaultBindingProperty>().FirstOrDefault();
    return att?.Name;
}

Side Note

You may be interested to these attributes as well for some complex scenarios:

• LookupBindingProperties : Specifies the properties that support lookup-based binding. List controls like ComboBox and ListBox are decorated by this attribute, [LookupBindingProperties("DataSource", "DisplayMember", "ValueMember", "SelectedValue")] .

• ComplexBindingProperties : Specifies the data source and data member properties for a component that supports complex data binding. DataGridView has been decorated by this attribute, [ComplexBindingProperties("DataSource", "DataMember")] .