Compiler Error CS1104
A parameter array cannot be used with 'this' modifier on an extension method.
The first parameter of an extension method cannot be a params array.
To correct this error
- Remember that the first parameter of an extension method definition specifies which type the method will "extend". It is not an input parameter. Therefore, it makes no sense to have a params array in this location. If you do have to pass in a params array, make it the second parameter.
Example
The following example generates CS1104:
// cs1104.cs
// Compile with: /target:library
public static class Extensions
{
public static void Test<T>(this params T[] tArr) {} // CS1104
}