Regular expression to match colon

Question

I need to add an interface to an class in c# and need to match if has already been declared:

public partial class Client

Needs to be

public partial class Client: IEntity

When the occurrence already exists

public partial class Client: IEntity

Must remain

I have reached this "public partial class (\\w+)" into "public partial class $1: IEntity"

Thanks.

Answer 1

If you only want to handle that specific type of format (ie "public partial class 'classname'"). Something like this would do it:

class Program
{
    static readonly Regex re = new Regex( @"^public partial class[^:]+$", RegexOptions.Compiled );
    static string Replacement( string stringToReplace )
    {
        return re.Replace( stringToReplace, match => match.Value + ": IEntity" );                
    }   
    static void Main()
    {
        string newString = Replacement( "public partial class Client" );
        Console.WriteLine( newString ); //output: "public partial class Client: IEntity"
        newString = Replacement( "public partial class Server" );
        Console.WriteLine( newString ); //output: "public partial class Server: IEntity"
        newString = Replacement( "public partial class Server: IEntity" );
        Console.WriteLine( newString ); //output: "public partial class Server: IEntity"
    }       
}

Where:

• ^ means match from the beginning.
• $ means match to the end.
• [^:]+ means any character not ':'

Answer 2

I'd say a straight up regex is a dangerous approach.

What if you have:

public partial class Client: RichClient

better be sure not to add an extra : IEntity

If it is possible you could maybe get the complete line text and then write a function to determine what to do.

Could there be a problem with spanning multiple lines?

Answer 3

看来您正在寻找这样的东西

(get-content test.cs -raw) -replace 'public partial class (\w+)(:.*)?$','public partial class $1: IEntity'