Regular expression for string not start with special caracter and space

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i have to make regular expression which not allow string start with sprecial caracter.
for exampel :
45@gf.com - right
@45gm.com - wrong

how can i do this ?

What I have tried:

i have make this regular expression...
string TrNo = txtConsignor.Text.ToString();
TrNo = System.Text.RegularExpressions.Regex.Replace(TrNo, "[^a-zA-Z0-9\\s]", "");
txtConsignor.Text = TrNo.TrimStart();

Posted 12-May-17 1:34am

Member 9720862

Updated 12-May-17 1:47am

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Patrice T 12-May-17 7:49am

You say something and your code does something else.
What do you want to do with your RegEx?
you want to validate a string or change the string ?

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OriginalGriff · Answer 1 · 2017-05-12T01:47:00

What you are doing doesn't prohibit special characters, it removes them. And it doesn't require them to be at the start, either!
So if your string is "@45gm.com" then it converts it to 45gmcom and doesn't tell anyone it's done it. So what gets stored (or otherwise processed) isn;t a valid email either, and gives problems way on down the line, when it's too late to fix it. Worse, it does the same thing with your "correct" string: "45@gf.com" becomes "45gfcom"

What you need is to use it as a regex and check the result:

C#

Match m = Regex.Match(trNo, "^[^a-zA-Z0-9\\s]");
if (m.Success)
    {
    ... report problem to user ...
    return;
    }