extension-methods

I am received the following error while trying to implement a C# extension function in XSLT. Extension function parameters or return values which have CLR type 'Char[]' are not supported.** code: <xsl:variable name="stringList"> <xsl:value-of select="extension:GetList('AAA BBB CCC', ' ')"/> </xsl:variable> <msxsl:script language="C#" implements-prefix="extension"> <![CDATA[ public string[] GetList(string str, char[] delimiter) { ... ... return str.Split(delimiter, StringSplitOptions.None); } ]]> </msxsl:script> Can someone explain this error message and how to get past it? EDIT: I need a

the question is really simple. How do we format strings in C#? this way: string.Format("string goes here with placeholders like {0} {1}", firstName, lastName); Now, is it possible to create an extension method to do it this way? "string goes here {0} {1}".Format(firstName, lastName); That's all. Well, it's more complicated than it looks. Others say this is possible, and I don't doubt them, but it doesn't seem to be the case in Mono. There, the standard overloads of the Format() method seem to take precedence in the name resolution process, and compilation fails because a static method ends up

Can someone explain to me why in the following the 3rd invocation of DoSomething is invalid? ( Error message is "The name 'DoSomething' does not exist in the current context" ) public class A { } public class B : A { public void WhyNotDirect() { var a = new A(); a.DoSomething(); // OK this.DoSomething(); // OK DoSomething(); // ?? Why Not } } public static class A_Ext { public static void DoSomething(this A a) { Console.WriteLine("OK"); } } Extension methods are still static methods, not true instance calls. In order for this to work you would need specific context using instance method syntax

I have an IEnumerable<T> , and I want to call the Enumerable.Contains method by reflection. I'm just struggling to get the syntax right. Here's what I currently have: var containsMethod = typeof(Enumerable).GetMethod("Contains", new[] { typeof(IEnumerable<T>), typeof(T) }); This just comes back with a null. What is the correct way to get the MethodInfo ? What is the correct way to get the MethodInfo? You have to find the generic method - which is unfortunately a bit of a pain - and then construct that with the appropriate arguments. In this case you know that there are only 2 Contains

For sake of simplicity, let's assume I want to write an extension method for the type int? and int: public static class IntExtentions { public static int AddOne(this int? number) { var dummy = 0; if (number != null) dummy = (int)number; return dummy.AddOne(); } public static int AddOne(this int number) { return number + 1; } } Can this be done using only 1 method? Unfortunately not. You can make the int? (or whichever nullable type you are using) method call the non nullable method very easily though, so you don't need to duplicate any logic with 2 methods - e.g. public static class

I have a series of extension methods defined for various classes in a C# library. I'm currently writing some F# code and instead of rewriting that code I would simply like to use my existing extension methods in my F# code. I have added a reference to the library and used the open statement to import the namespace, but the extension methods to not appear in F# Update: In the current version of F#, you can simply consume extension methods by adding open TheNamespaceOfExtensionMethod to your source file (just like you do in C# with a using directive) and simply call the extension method as if it