提取属性参数值

Question

我可以从NUnit测试类库程序集中检索所有测试名称，但还需要从传递给Category属性的参数中检索它们的类别名称。

例如：

[Category("text")] 
public void test() {}

我需要从动态链接库拿到"text"。

Answer 1

使用反射。

例如：

假设此属性应用于字段：

<AttributeUsage(AttributeTargets.Field)> _
     Public NotInheritable Class DataBaseValueAttribute
    Inherits Attribute

    Private _value As Object

    Public Sub New(ByVal value As Object)
      _value = value
    End Sub

    Public Function GetValue() As Object
      Return _value
    End Function
  End Class

您可以使用反射从类型中获取字段信息并获取属性：

Dim tipo As Type = GetType(YourType)
Dim fi As FieldInfo = tipo.GetField("fieldName")

Dim attribs As Atributos.DataBaseValueAttribute() = CType(fi.GetCustomAttributes(GetType(Atributos.DataBaseValueAttribute), False), Atributos.DataBaseValueAttribute())
If attribs.Count > 0 Then
   Return attribs(0).GetValue()
Else
   Return Nothing
End If

在c#中：

[AttributeUsage(AttributeTargets.Field)]
public sealed class DataBaseValueAttribute : Attribute
{
    private object _value;
    public DataBaseValueAttribute(object value)
    {
        _value = value;
    }

    public object GetValue()
    {
        return _value;
    }
}

Type tipo = typeof(YourType);
FieldInfo fi = tipo.GetField("fieldName");

Atributos.DataBaseValueAttribute[] attribs = (Atributos.DataBaseValueAttribute[])fi.GetCustomAttributes(typeof(Atributos.DataBaseValueAttribute), false);
if (attribs.Count > 0) {
    return attribs(0).GetValue();
} else {
    return null;
}