How to hide the current method from exception stack trace in .NET?

Using the code at the end of this answer allows you to write code such as:

[HideFromStackTrace] // apply this to all methods you want omitted in stack traces
static void ThrowIfNull(object arg, string paramName)
{
    if (arg == null) throw new ArgumentNullException(paramName);
}

static void Foo(object something)
{
    ThrowIfNull(something, nameof(something));
    …
}

static void Main()
{
    try
    {
        Foo(null);
    }
    catch (Exception e)
    {
        Console.WriteLine(e.GetStackTraceWithoutHiddenMethods());
    }                  // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
}                      // gets a stack trace string representation
                       // that excludes all marked methods

Here’s one possible implementation:

using System;
using System.Diagnostics;
using System.Linq;
using System.Reflection;

[AttributeUsage(AttributeTargets.Method, Inherited=false)]
public class HideFromStackTraceAttribute : Attribute { }

public static class MethodBaseExtensions
{
    public static bool ShouldHideFromStackTrace(this MethodBase method)
    {
        return method.IsDefined(typeof(HideFromStackTraceAttribute), true);
    }
}

public static class ExceptionExtensions
{
    public static string GetStackTraceWithoutHiddenMethods(this Exception e)
    {
        return string.Concat(
            new StackTrace(e, true)
                .GetFrames()
                .Where(frame => !frame.GetMethod().ShouldHideFromStackTrace())
                .Select(frame => new StackTrace(frame).ToString())
                .ToArray());  // ^^^^^^^^^^^^^^^     ^
    }                         // required because you want the usual stack trace
}                             // formatting; StackFrame.ToString() formats differently

Note that this only causes marked methods to be excluded from one particular representation of the stack trace, not from the stack trace itself. I know of no way to achieve the latter.

P.S.: If all you want is to hide a method in the Call Stack window during a debugging session, simply apply the [DebuggerHidden] attribute to the method.