DataBinding(String, Type, String) 构造函数

定义

命名空间:

System.Web.UI

程序集:

System.Web.dll

初始化 DataBinding 类的新实例。

public:
 DataBinding(System::String ^ propertyName, Type ^ propertyType, System::String ^ expression);

public DataBinding (string propertyName, Type propertyType, string expression);

new System.Web.UI.DataBinding : string * Type * string -> System.Web.UI.DataBinding

Public Sub New (propertyName As String, propertyType As Type, expression As String)

参数

propertyName

String

要数据绑定到的属性。

propertyType

Type

要数据绑定到的属性的 .NET Framework 类型。

expression

String

要计算的数据绑定表达式。

示例

下面的代码示例创建一个 DataBinding 对象并将其设置为控件集合 DataBindingCollection 中的现有对象，该对象具有 propertyName 值 Text的参数。 如果集合包含一个DataBinding值为的对象propertyName``Text，则此代码返回对象的Expression属性的值。 如果没有此类对象，它将返回空字符串 (“”) 。

// Create a Text property with accessors that obtain 
// the property value from and set the property value
// to the Text key in the DataBindingCollection class.
public string Text
{
    get
    {
        DataBinding myBinding = DataBindings["Text"];
        if (myBinding != null)
        {
            return myBinding.Expression;
        }
        return String.Empty;
    }
    set
    {

        if ((value == null) || (value.Length == 0))
        {
            DataBindings.Remove("Text");
        }
        else
        {

            DataBinding binding = DataBindings["Text"];

            if (binding == null)
            {
                binding = new DataBinding("Text", typeof(string), value);
            }
            else
            {
                binding.Expression = value;
            }
            // Call the DataBinding constructor, then add
            // the initialized DataBinding object to the 
            // DataBindingCollection for this custom designer.
            DataBinding binding1 = (DataBinding)DataBindings.SyncRoot;
            DataBindings.Add(binding);
            DataBindings.Add(binding1);
        }
        PropertyChanged("Text");
    }
}

' Create a Text property with accessors that obtain 
' the property value from and set the property value
' to the Text key in the DataBindingCollection class.

Public Property [Text]() As String
    Get
        Dim myBinding As DataBinding = DataBindings("Text")
        If Not (myBinding Is Nothing) Then
            Return myBinding.Expression
        End If
        Return String.Empty
    End Get
    Set(ByVal value As String)

        If value Is Nothing OrElse value.Length = 0 Then
            DataBindings.Remove("Text")
        Else

            Dim binding As DataBinding = DataBindings("Text")

            If binding Is Nothing Then
                binding = New DataBinding("Text", GetType(String), value)
            Else
                binding.Expression = value
            End If
            ' Call the DataBinding constructor, then add
            ' the initialized DataBinding object to the 
            ' DataBindingCollection for this custom designer.
            Dim binding1 As DataBinding = CType(DataBindings.SyncRoot, DataBinding)
            DataBindings.Add(binding)
            DataBindings.Add(binding1)
        End If
        PropertyChanged("Text")
    End Set
End Property

另请参阅

• DataBinder