Question

我正在尝试使用

获取动态linq列的类型

var args = ((dynamic)linqColumn).PropertyType.GenericTypeArguments;

然后比较可能的类型名称：

if (args.Length > 0 && args[0].Name == "DateTime")
    ProcessDateTimeType();
else if (args.Length > 0 && args[0].Name == "Double")
    ProcessDoubleType();

这适用于带有.NET 4.0的Windows Vista，但不适用于带有.NET 4.0的Windows Server 2003。错误'System.Type' does not contain a definition for 'GenericTypeArguments'被抛出。

我只需要GelableTypeArguments用于可空类型。

有什么想法吗？

说明

linqColumn是通过var linqColumn = linqTableType.GetProperty("COLNAME");
linqTableType是通过'Type linqTableType = Type.GetType("MYNAMESPACE." + "TABLENAME");
代码在里面执行网络服务

Answer 1

As Preston mentioned in the comments, the GenericTypeArguments property was added in .NET 4.5.

4.5 is an in-place upgrade to 4.0; even though you're targeting 4.0, the 4.5 APIs will still work when you use reflection or dynamic.

Try limiting the dynamic code to just the part that retrieves the property type; from that point on, you know the value is a Type, so you can use early binding:

Type propertyType = ((dynamic)linqColumn).PropertyType;

// Visual Studio should now warn you if you try to use:
// var args = propertyType.GenericTypeArguments;

var args = propertyType.IsGenericType && !propertyType.IsGenericTypeDefinition
    ? propertyType.GetGenericArguments()
    : Type.EmptyTypes;

＆＃39; System.Type的＆＃39;不包含＆＃39; GenericTypeArguments＆＃39;的定义用（动态）

1 个答案: