I Have A String Variable Like String A = "Name:Venkat,Phno:77089,City:Test" I Want To Get Venkat And 77089 And Test Values And Store Separate Variable Using C#

You can also do the same using Regular Expression.

String tmp = @":(\w+)";
String input = "Name:venkat,PhNo:77089,City:Test";

Regex exp = new Regex(tmp);
MatchCollection col = exp.Matches(input);

You can further eliminate ":" in the array

Further to the other solutions...

You can split on multiple characters. For example

string A = "Name:venkat,PhNo:77089,City:Test";

//Attempt 1 - split on both : and , to get all of the parts separately
var attempt1 = A.Split(':',',');
foreach (var s in attempt1)
    Console.WriteLine(s);
Console.WriteLine("Stuff I need : {0}, {1}, {2}", attempt1[1], attempt1[3], attempt1[5]);

gives results of

Name
venkat
PhNo
77089
City
Test
Stuff I need : venkat, 77089, Test

Which is fine if the data Is always in that order. But what if this string is a string of named parameters to a console application for example. Imagine the user has not quite got it right and sends in a string that looks like

A = "Name:venkat,City:Test,Another:Thing,PhNo:77089";

Then you would get

Stuff I need : venkat, Test, Thing

Hm, not what I was wanting.

However, if you split just on the comma (,) you will essentially get a list of paired data itemname:value

A = "Name:venkat,City:Test,Another:Thing,PhNo:77089";
var attempt2 = A.Split(',');
foreach (var s in attempt2)
    Console.WriteLine(s);

gives results

Name:venkat
Another:Thing
City:Test
PhNo:77089

which you can then search for the items you need rather than using hard-code positions

//Find just the PhNo
var res = attempt2.ToList()
                    .Find(x => x.StartsWith("PhNo"))
                    .Split(':')
                    [1];
Console.WriteLine("The Phone number: {0}", res);

gives

The Phone number: 77089

Obviously a lot more long-winded than the first attempt, and longer-winded than the regex solution, but I suggest more flexible, particularly if you have more items to add to the list.