How to replace a matched group value with Regex

Question

I would like to modify the value of the "data source" component in a connection string. I'm thinking of the following solution:

Using this regex pattern:

"data source\=((\w|\-)+?\\{1}\w+?)\;"

I can obtain the following string matches:

Match.Groups[0].Value = "data source=MY-PC\SQLEXPRESS;"
Match.Groups[1].Value = "MY-PC\SQLEXPRES"

So in the connection string firstly I would like to find the part matching with the "data source=something;", and secondly replace just the "something" in the connection string. How to do that?

Answer 1

If you insist Regex replacing, please note C# cannot modify a built string, you need to get a new string with the needed part replaced.

var connectionString = @"data source=MY-PC\SQLEXPRESS;";
var pattern = @"(data source=)((\w|\-)+?\\\w+?)\;";
var newConnectionString = Regex.Replace(connectionString, pattern, "$1" + "something");
Console.WriteLine(newConnectionString);

Answer 2

For most connection string types in .NET there should be a corresponding ConnectionStringBuilder class to handle this sort of thing. How are you connecting to your DB?

Answer 3

Just replace it.

string dbSource = "data source=myserver\\sqlexpress";

int sLen = dbSource.IndexOf("=") + 1;
string getString = dbSource.Substring(sLen, dbSource.Length - sLen);

dbSource = dbSource.Replace(getString, "whatyouwantotoreplaceitwith");

Answer 4

You can split your matches further by using simple string.split with '=' character or if you like regular expressions see MSDN Regex.Replace Method