How to get the type of a property used within a generic expression?
c# expression expression-trees generics
Question
public static void Map<T>(Expression<Func<T, object >> expression)
{
var memberExpression = (expression.Body as UnaryExpression).Operand as MemberExpression;
var name = memberExpression.Member.Name;
}
Usage:
Map<Article>(x => x.Name)
Name is of type string.
How do I get the type?
Accepted Answer
var returnType = memberExpression.Member is MethodInfo
? ((MethodInfo)memberExpression.Member).ReturnType
: ((PropertyInfo)memberExpression.Member).PropertyType;
I assume you want the return type. If you want the type on which the method is defined, use memberExpression.Member.DeclaringType.
Popular Answer
Here is a simple Expression Extension Method that may be useful to others.
public static Type GetPropertyType<TModel, TValue>(this Expression<Func<TModel, TValue>> expression)
{
var body = expression.Body as MemberExpression;
if (body == null)
{
throw new ArgumentException("'expression' should be a member expression");
}
return ((PropertyInfo)body.Member).PropertyType;
}
Sample usage:
if (expression.GetPropertyType() == typeof(DateTime))
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