Must declare scalar variable in login form

Question

I am getting error "Must declare scalar variable @uname and @pw". I have tried many methods but its not working. please guide me to find the issue in my belo code. private void button1_Click( object sender, EventArgs e) { OleDbConnection con = new OleDbConnection(@ "Provider=SQLOLEDB;Data Source=DESKTOP\SQLEXPRESS;User ID=sa; Password = pwd; Initial Catalog=database; Integrated secutity=SSPI" ); con.Open(); OleDbCommand cmd = new OleDbCommand( "select Username,password from login where Username=@uname and password=@pw" , con); OleDbDataAdapter da = new OleDbDataAdapter(cmd); cmd.Parameters.Clear(); //cmd.Parameters.AddWithValue("@uname", textBox1.Text); //cmd.Parameters.AddWithValue("@pw", textBox1.Text); DataTable dt = new DataTable(); da.Fill(dt); if (dt.Rows.Count > 0) { MessageBox.Show( "success" ); } else { MessageBox.Show( "incorrect" ); } con.Close();}

Amit Gupta · Answer

You just need to uncomment the code that you had commented, error occurs because you had use scalar variable that starts with @

Rajanikant Hawaldar · Answer

Hi Meena S, Go through below code, first identity what you missed in your code with this code. public class DBConnection { public static SqlConnection GetConnection() { // retrive Connection string from Appconfig file return SqlConnection conn = new sqlConnection(ConfigurationManager.ConnectionString[ "MyConn" ].ConnectionString); } public static bool CheckLogin( string UserName, string UserPass) { string selectString = "SELECT username, password " + "FROM forum_members " + "WHERE username = '" + UserName + "' AND password = '" + UserPass + "'" ; var conn=GetConnection(); SqlCommand mySqlCommand = new MySqlCommand(selectString, conn); conn.Open(); String strResult = String.Empty; strResult = (String)SqlCommand.ExecuteScalar(); conn.Close(); if (strResult.Length == 0) return false ; else return true } }

Madan Shekar · Answer

sql query in your controller string username=""; string emailid=""; public void getUser(string emailaddress,string password string dbcon) { string query = string.Empty; query = "select * from vtuser where emailaddress=@emailaddress and password=@password"; if (IsSSO) { query = "select * from table name where loginname=@emailaddress"; } SqlCommand cmd = new SqlCommand(query); cmd.Parameters.AddWithValue("@emailaddress", emailaddress); cmd.Parameters.AddWithValue("@password ", password DataTable dt = sqlExceute(cmd, dbcon); User user = new User(); if (dt.Rows.Count > 0) { foreach (DataRow rows in dt.Rows) { if (rows["username"] != DBNull.Value) { username = Convert.ToString(rows["username"]); } if (rows["userid"] != DBNull.Value) { emailid = Convert.ToString(rows["email"]); } } } } public static DataTable sqlExceute(SqlCommand cmd, string dbcon) { Trace.TraceInformation("Inside sqlExecute"); SqlConnection Con = new SqlConnection(dbcon); DataTable dT = new DataTable(); int retryCount = 0; cmd.Connection = Con; retry: try { Trace.TraceInformation("before sqlExecute-retryCount-" + retryCount); if (retryCount { Con.Open(); using (SqlDataAdapter dA = new SqlDataAdapter(cmd)) { dA.Fill(dT); } Con.Close(); } Trace.TraceInformation("after sqlExecute completes-retryCount-" + retryCount); } catch (SqlException ex) { Trace.TraceInformation("Error in sqlExecute-" + ex.Message); Thread.Sleep(TimeSpan.FromSeconds(1)); Con.Close(); retryCount++; goto retry; } return dT; }

Must declare scalar variable in login form

Answers (3)