User login module using c# code with password encryption not working

Question

Iam retrieving the user from sql users table which password was encrypted using HASHBYTES SHA1.

Dataset retrive only null value.

public  class UserModelClass
{
    public int Id { get; set; }
    public string UserName { get; set; }
    public int Authentication { get; set; }
    public string FullName { get; set; }
    public string Address { get; set; }
    public string Tel { get; set; }
    public int Encrypted { get; set; }
    public string Password { get; set; }
}

public static DataTable CheckUser(UserModelClass us)
{
    string sql = "SELECT TOP 1 1 FROM Users WHERE UserName=@username AND Password=HASHBYTES('SHA1',@Password)";
    using (SqlConnection con = new SqlConnection(DbConnection.GetConnectionString()))
    {
        using (SqlDataAdapter adapter = new SqlDataAdapter(sql, con))
        {
            adapter.SelectCommand.Parameters.AddWithValue("@UserName", us.UserName);
            adapter.SelectCommand.Parameters.AddWithValue("@password",  us.Password);
            DataSet ds = new DataSet();
            adapter.Fill(ds, "Users");
            return ds.Tables[0];
        }
    }
}

Answer 1

You need to change this line:

string sql = "SELECT TOP 1 1 FROM Users WHERE UserName=@username AND Password=HASHBYTES('SHA1',@Password)";

With this line:

string sql = "SELECT TOP 1 1 FROM Users WHERE UserName=@username AND Password= convert(nvarchar(max),HASHBYTES('SHA1',@password),1)";

nvarchar (max) must match the data type on the table change it based on the type you have on the password field