C# Extension Method - Check if string is (not) null/empty

/// <summary>
/// Checks if the string is NULL or empty, then returns true, otherwise returns false.
/// Example:
///     if (someTextBox.Text.IsNullOrEmpty())
///     {
///         // handle as true (empty)...
///     }
///     else
///     {
///         // handle as false (not empty)...
///     }
/// </summary>
/// <param name="inString"></param>
/// <returns></returns>
public static bool IsNullOrEmpty(this string inString)
{
    if (inString == null)
        return true;
    else if (inString.Trim() == string.Empty)
        return true;
    else
        return false;
}

/// <summary>
/// Determines whether string is not null or empty.
/// </summary>
/// <param name="input">The input.</param>
/// <returns>
///   <c>true</c> if [is not null or empty] [the specified input]; otherwise, <c>false</c>.
/// </returns>
public static bool IsNotNullOrEmpty(this string input)
{
    return !String.IsNullOrEmpty(input);
}