case consrtuct of sql in asp.net

I want to use case construct of SQL:

CASE WHEN ans='A' THEN 1 ELSE 0 END

(Where ans is a string declared in ASP.NET) in an insert query like:

SqlCommand AnsCmd = new SqlCommand("insert into开发者_StackOverflow answers(ans_desc,istrue)values('" + ans1_desc + "',CASE WHEN ans='A' THEN 1 ELSE 0 END)", conn);

But it is not working... maybe the syntax is wrong? Please help.

It seems like the problem is at the ans variable you use. You should declare it at your query before use it at your CASE statement.

DECLARE @ans varchar(1);
SET @ans = 'A';
INSERT INTO answers(ans_desc,istrue)
VALUES('answer desc',CASE WHEN @ans='A' THEN 1 ELSE 0 END);

The SQL variable ans is declared nowhere in your SQL statement. Where does it come from? Sql or your ASP.NET app?