C# - methods and return value of Boolean type

Question

Hello !
I'am rather new to C#, but have som programing experience in VBA and VB. I'am learning Visual development in C#.
Problem:
I'am trying to call a method with a string value and to have the called method to return a boolean false value indicating that a lookup in the database returned a value that allready exists. I recieve an error that says: not all code paths return a value . Thanks in advance,
Here's the code:
chkFrm(ddlCompany.Text);
public Boolean chkFrm( string searchParam)
{
string ddlComp = "'" + searchParam + "%" + "'" ;
string sql = @"SELECT Name FROM Company WHERE Name LIKE " + ddlComp;
SqlConnection con = new SqlConnection (
"data source=.;initial catalog=survSys;" +
"user id=laho;pwd=12345" );
SqlCommand cmd = new SqlCommand (sql, con);
con.Open();
string name = null ;
try
{
name = ( string )cmd.ExecuteScalar();
if (name != null )
{
return false ;
}
}
finally
{
con.Close();
}
}

Larry Hojer · Answer

Thanks again Alan.
I'am learning the C# syntax and somtimes you need this simple but great help.
Thanks again,

Alan · Answer

When you have a method which returns some value, the C# compiler tracks through the code to make sure that, whatever path is followed, a value will always be returned. The compiler, of course, doesn't really 'understand' what the code does - it just follows some rather complicated rules based on the structure of the code and the syntax of the language.
As you had it originally, this wasn't the case if 'name' was null but adding the 'else' clause solved this problem.
I think it would also have worked if you'd placed a 'return true;'  statement after the 'finally' close and just before the end of the method.

Larry Hojer · Answer

Thanks Alan, it now works as I whant it to.
Why do you need the extra ELSE clause?

Alan · Answer

The method only has a return value (namely 'false') if name is not null.
To get rid of the compiler error, you could place an else clause in there:
try
{
name = ( string )cmd.ExecuteScalar();
if (name != null )
{
return false ;
}
else
{
return true ;
}
}
finally
{
con.Close();
}