System.Reflection.AmbiguousMatchException: 'Ambiguous match found.'

Question

I am trying to get the MethodInfo from a method TableExists<T> so I can call it with a type.

The method is declared inside OrmLiteSchemaApi class. There are 2 overloads:

public static bool TableExists<T>(this IDbConnection dbConn)
{
  // code omitted
}

public static bool TableExists(this IDbConnection dbConn, string tableName, string schema = null)
{
  // code omitted
}

I am trying to get the MethodInfo like this:

var tableMethod = typeof(OrmLiteSchemaApi).GetMethod("TableExists");

But it generates exception:

System.Reflection.AmbiguousMatchException: 'Ambiguous match found.'

I could only find an old question related to this that suggested to pass an empty object array as parameter but this doesn't seem to work for .net core.

I guess I need to specify the specific overload but I am not sure exactly how.

How do I get the MethodInfo?

Answer 1

You can use GetMethods (plural!) to get an array of all matching methods, and then look for the one which has IsGenericMethod:

var tm = typeof(OrmLiteSchemaApi)
        .GetMethods()
        .Where(x => x.Name == "TableExists")
        .FirstOrDefault(x => x.IsGenericMethod);

I recommend this over using parameter specifiers, since it'll give you an object you can step through at debug time if there are ever any problems.

Answer 2

Passing an empty object array would only work if you're looking for a function with no parameters. Instead, you need to use a different overload of GetMethod that specifies the types of parameters as a type array. That way you can tell it which reference to get by specifying which types of parameters it should look for.