Must declare scalar variable in login form

Meena S

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();}

3 Replies

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Amit Gupta7y ago
You just need to uncomment the code that you had commented, error occurs because you had use scalar variable that starts with @
Rajanikant Hawaldar7y ago
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 Shekar7y ago
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 < 3)
{
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;
}