Fuzzy Lookup using parameterized SQL statements (reproduced)

Today I want to use parameterized SQL statements for Fuzzy Lookup, the first use of the method is not correct, groped for a good while.

1. The correct method for fuzzy lookups using parameterized SQL statements:

Defining SQL statements

String sql = "Select Studentid,studentno,studentname from Student WHERE studentname like @StudentName";

assigning values to parameters

Command. Parameters.addwithvalue ("@StudentName", txtstudentname.text+ "%");

2. Error procedure 1:

Defining SQL statements

String sql = "Select Studentid,studentno,studentname from Student WHERE studentname like ' @StudentName% '";

assigning values to parameters

Command. Parameters.addwithvalue ("@StudentName", Txtstudentname.text);

3. Error Procedure 2:

Defining SQL statements

String sql = "Select Studentid,studentno,studentname from Student WHERE studentname like @StudentName%";

assigning values to parameters

Command. Parameters.addwithvalue ("@StudentName", Txtstudentname.text);

Fuzzy Lookup using parameterized SQL statements (reproduced)