While save button click error converting data type varchar to int WPF C#

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private void btnSave_Click(object sender, RoutedEventArgs e)
       {
           try
           {
               if (isValid())
               {
                   SqlConnection conn = new SqlConnection(ConnectionString);
                   conn.Open();
                   SqlCommand cmd = new SqlCommand("add_user_details", conn);
                   cmd.CommandType = CommandType.StoredProcedure;
                   cmd.Parameters.AddWithValue("@id", SqlDbType.Int).Value = string.IsNullOrWhiteSpace(txtUserId.Text) ? DBNull.Value : (object)txtUserId.Text;
                   cmd.Parameters.AddWithValue("@emp_id", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(cmboSelEmp.Text) ? DBNull.Value : (object)cmboSelEmp.Text;
                   cmd.Parameters.AddWithValue("@emp_name", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(cmboSelEmp.Text) ? DBNull.Value : (object)cmboSelEmp.Text;
                   cmd.Parameters.AddWithValue("@usertype", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(cmboSelUser.Text) ? DBNull.Value : (object)cmboSelUser.Text;
                   cmd.Parameters.AddWithValue("@privilege", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(cmboSelUser.Text) ? DBNull.Value : (object)cmboSelUser.Text;
                   cmd.Parameters.AddWithValue("@username", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(txtUsername.Text) ? DBNull.Value : (object)txtUsername.Text;
                   cmd.Parameters.AddWithValue("@password", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(txtPassword.Password) ? DBNull.Value : (object)txtPassword.Password;
                   cmd.Parameters.AddWithValue("@branch", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(cmboBranch.Text) ? DBNull.Value : (object)cmboBranch.Text;
                   //SqlCommand cmd = new SqlCommand("add_user_details'" + txtUserId.Text + "','" + cmboSelEmp.SelectedValuePath + "'," +
                   //    "'" + cmboSelEmp.Text+ "','" + cmboSelUser.SelectedValuePath+ "'," +
                   //    "'" + cmboSelUser.SelectedValuePath + "','" + txtUsername.Text + "','" + txtPassword.Password.ToString() + "'," +
                   //    "'" + cmboBranch.Text + "'", con);
                   cmd.ExecuteNonQuery();
                   conn.Close();
                   MessageBox.Show("Successfully saved", "Fill Field", MessageBoxButton.OK, MessageBoxImage.Information);
                   refresh();
               }
           }
           catch (SqlException ex)
           {
               MessageBox.Show(ex.Message);
           }
       }

What I have tried:

<pre> private void btnSave_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                if (isValid())
                {
                    SqlConnection conn = new SqlConnection(ConnectionString);
                    conn.Open();
                    SqlCommand cmd = new SqlCommand("add_user_details", conn);
                    cmd.CommandType = CommandType.StoredProcedure;
                    cmd.Parameters.AddWithValue("@id", SqlDbType.Int).Value = string.IsNullOrWhiteSpace(txtUserId.Text) ? DBNull.Value : (object)txtUserId.Text;
                    cmd.Parameters.AddWithValue("@emp_id", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(cmboSelEmp.Text) ? DBNull.Value : (object)cmboSelEmp.Text;
                    cmd.Parameters.AddWithValue("@emp_name", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(cmboSelEmp.Text) ? DBNull.Value : (object)cmboSelEmp.Text;
                    cmd.Parameters.AddWithValue("@usertype", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(cmboSelUser.Text) ? DBNull.Value : (object)cmboSelUser.Text;
                    cmd.Parameters.AddWithValue("@privilege", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(cmboSelUser.Text) ? DBNull.Value : (object)cmboSelUser.Text;
                    cmd.Parameters.AddWithValue("@username", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(txtUsername.Text) ? DBNull.Value : (object)txtUsername.Text;
                    cmd.Parameters.AddWithValue("@password", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(txtPassword.Password) ? DBNull.Value : (object)txtPassword.Password;
                    cmd.Parameters.AddWithValue("@branch", SqlDbType.VarChar).Value = string.IsNullOrWhiteSpace(cmboBranch.Text) ? DBNull.Value : (object)cmboBranch.Text;
                    //SqlCommand cmd = new SqlCommand("add_user_details'" + txtUserId.Text + "','" + cmboSelEmp.SelectedValuePath + "'," +
                    //    "'" + cmboSelEmp.Text+ "','" + cmboSelUser.SelectedValuePath+ "'," +
                    //    "'" + cmboSelUser.SelectedValuePath + "','" + txtUsername.Text + "','" + txtPassword.Password.ToString() + "'," +
                    //    "'" + cmboBranch.Text + "'", con);
                    cmd.ExecuteNonQuery();
                    conn.Close();
                    MessageBox.Show("Successfully saved", "Fill Field", MessageBoxButton.OK, MessageBoxImage.Information);
                    refresh();
                }
            }
            catch (SqlException ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

Posted 6-Sep-22 22:37pm

prashanth manoj

Updated 6-Sep-22 23:11pm

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Comments

Richard Deeming 7-Sep-22 8:04am

You are storing your users' passwords in plain text. Don't do that! Instead, store a salted and stretched hash of the password, using a cryptographically secure one-way hash algorithm.

Secure Password Authentication Explained Simply[^]
Salted Password Hashing - Doing it Right[^]

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2022-09-06T23:11:00

That's not a WPF problem: it's what you are sending to SQL.

C#

cmd.Parameters.AddWithValue("@id", SqlDbType.Int).Value = string.IsNullOrWhiteSpace(txtUserId.Text) ? DBNull.Value : (object)txtUserId.Text;

You don't show any code which validates any of your text boxes, so if txtUserId contains any non-numeric characters then the conversion will fail and your SQL will not work.

It's generally a good idea to validate and convert user input at the start of the method, then only continue if valid data has been entered.

C#

if (!int.TryParse(txtUserId.Text, out int id))
    {
    ... report a problem ...
    return;
    }

You can then use the id value directly in your SQL without any null checking:

C#

cmd.Parameters.AddWithValue("@id", SqlDbType.Int).Value = id;

While save button click error converting data type varchar to int WPF C#

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While save button click error converting data type varchar to int WPF C#

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