dynamic login based on accdb database for login form?

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I have this code on button to login and open main form

KorisnikLozinkaString is sql built on dataset and it works fine there.
datasource is accdb database which has usernames and passwords

Korisnik is username
Lozinka is password

C#

private void button1_Click(object sender, EventArgs e)

dynamic login = this.usersTableAdapter2.KorisnikLozinkaString(textBox1.Text, textBox2.Text);

{
if (login == null)
MessageBox.Show("Wrong Entry");
}

???????

and I don't know how to make it to work, I need the if or else statement that will open allow logging in and opening main form.

help

Posted 18-Feb-11 5:17am

shonezi

Updated 18-Feb-11 5:27am

Henry Minute

v4

Add a Solution

2 solutions

Solution 1

It's hard to know what you are doing without seeing what the KorisnikLozinkaString method does.

Posted 18-Feb-11 5:37am

Nish Nishant

Comments

shonezi 18-Feb-11 11:41am

SELECT COUNT(*) AS Result, Korisnik AS KorisnikInput, Lozinka AS LozinkaInput
FROM users
GROUP BY Korisnik, Lozinka
HAVING (COUNT(*) = 1) AND (Korisnik = ?) AND (Lozinka = ?)

Nish Nishant 18-Feb-11 11:45am

Can you show the designer generated method though? This is the SQL, I am looking for the C# code.

Nish Nishant 18-Feb-11 11:56am

Can you right click on KorisnikLozinkaString and select go to definition? That will take you to the method directly. And then you can copy/paste just that method.

shonezi 18-Feb-11 11:48am

this is form called Login with two textboxes and button, I have another form which I want to to open when typing in proper username and password click on button to open. I am new to C# and visual studio.

namespace ATM
{
public partial class Login : Form
{
public Login()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{

dynamic login = this.usersTableAdapter2.KorisnikLozinkaString(textBox1.Text, textBox2.Text);

{
if (login == null)
MessageBox.Show("Wrong entry");

}

}

}
}

Nish Nishant 18-Feb-11 11:51am

The designer generates code for you. It will be a file named xxx.designer.cs (where xxx is your class name). Can you copy/paste the method here?

shonezi 18-Feb-11 11:52am

namespace ATM
{
partial class Login
{
///

/// Required designer variable.
///

private System.ComponentModel.IContainer components = null;

///

/// Clean up any resources being used.
///

/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}

#region Windows Form Designer generated code

///

/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
///

private void InitializeComponent()
{
this.label1 = new System.Windows.Forms.Label();
this.label2 = new System.Windows.Forms.Label();
this.textBox1 = new System.Windows.Forms.TextBox();
this.textBox2 = new System.Windows.Forms.TextBox();
this.label3 = new System.Windows.Forms.Label();
this.button1 = new System.Windows.Forms.Button();
this.usersTableAdapter2 = new ATM.ATMDataSetTableAdapters.usersTableAdapter();
this.SuspendLayout();
//
// label1
//
this.label1.AutoSize = true;
this.label1.Location = new System.Drawing.Point(182, 69);
this.label1.Name = "label1";
this.label1.Size = new System.Drawing.Size(44, 13);
this.label1.TabIndex = 0;
this.label1.Text = "Korisnik";
//
// label2
//
this.label2.AutoSize = true;
this.label2.Location = new System.Drawing.Point(182, 96);
this.label2.Name = "label2";
this.label2.Size = new System.Drawing.Size(44, 13);
this.label2.TabIndex = 1;
this.label2.Text = "Lozinka";
//
// textBox1
//
this.textBox1.Location = new System.Drawing.Point(244, 66);
this.textBox1.Name = "textBox1";
this.textBox1.Size = new System.Drawing.Size(100, 20);
this.textBox1.TabIndex = 2;
//
// textBox2
//
this.textBox2.Location = new System.Drawing.Point(244, 93);
this.textBox2.Name = "textBox2";
this.textBox2.PasswordChar = '*';
this.textBox2.Size = new System.Drawing.Size(100, 20);
this.textBox2.TabIndex = 3;
this.textBox2.UseSystemPasswordChar = true;
//
// label3
//
this.label3.AutoSize = true;
this.label3.Font = new System.Drawing.Font("Arial", 12F, ((System.Drawing.FontStyle)((System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic))), System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.label3.Location = new System.Drawing.Point(137, 275);
this.label3.Name = "label3";
this.label3.Size = new System.Drawing.Size(276, 18);
this.label3.TabIndex = 41;
this.label3.Text = "SEKTOR ZA TELEKOMUNIKACIJE";
//
// button1
//
this.button1.Font = new System.Drawing.Font("Arial", 14.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.button1.Location = new System.Drawing.Point(185, 136);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(159, 32);
this.button1.TabIndex = 42;
this.button1.Text = "OTVORI";
this.button1.UseVisualStyleBackColor = true;
this.button1.Click += new System.EventHandler(this.button1_Click);
//

Nish Nishant 18-Feb-11 11:55am

Ok, I don't think it pasted correctly (there's a maximum limit). I don't want to see the whole file anyway.

Can you right click on KorisnikLozinkaString and select go to definition? That will take you to the method directly. And then you can copy/paste just that method.

shonezi 18-Feb-11 11:56am

public virtual global::System.Nullable<int> KorisnikLozinkaString(string Korisnik, string Lozinka) {
global::System.Data.OleDb.OleDbCommand command = this.CommandCollection[1];
if ((Korisnik == null)) {
command.Parameters[0].Value = global::System.DBNull.Value;
}
else {
command.Parameters[0].Value = ((string)(Korisnik));
}
if ((Lozinka == null)) {
command.Parameters[1].Value = global::System.DBNull.Value;
}
else {
command.Parameters[1].Value = ((string)(Lozinka));
}
global::System.Data.ConnectionState previousConnectionState = command.Connection.State;
if (((command.Connection.State & global::System.Data.ConnectionState.Open)
!= global::System.Data.ConnectionState.Open)) {
command.Connection.Open();
}
object returnValue;
try {
returnValue = command.ExecuteScalar();
}
finally {
if ((previousConnectionState == global::System.Data.ConnectionState.Closed)) {
command.Connection.Close();
}
}
if (((returnValue == null)
|| (returnValue.GetType() == typeof(global::System.DBNull)))) {
return new global::System.Nullable<int>();
}
else {
return new global::System.Nullable<int>(((int)(returnValue)));

Nish Nishant 18-Feb-11 11:58am

Okay thanks, so that method seems right.

One thing to try is to run the SQL directly and see what it returns?

Nish Nishant 18-Feb-11 11:59am

Remember that while the SQL may return a row (with the count), it does not mean that that will automatically translate into a return value.

shonezi 18-Feb-11 12:04pm

well it returns row with the proper user, I mean it works because if I type wronf entry it doesnt return anything

Nish Nishant 18-Feb-11 12:06pm

Okay, so when you enter wrong username/password it returns null?

Nish Nishant 18-Feb-11 12:07pm

I mean, when you call the method with a wrong username/password, is the return value different from when you pass the correct username/password.

shonezi 18-Feb-11 12:11pm

on wrong user,pass
opens window it says
ATMDataSet.users.KorisnikLozinkaString(Korisnik,Lozinka) could not be previewed.
Parameter ?_1 has no default value.

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shonezi · Accepted Answer · 2011-02-20T00:07:00

I found a solution, easy one, right in front of my eyes:

private void button1_Click(object sender, EventArgs e)
{
dynamic login = this.usersTableAdapter2.KorisnikLozinkaString(textBox1.Text, textBox2.Text);
if (login == null)
{
MessageBox.Show("Wrong entry");
}
else
{
MessageBox.Show(Succesfull login");
mainForm main = new MainForm();
main.Show();
this.Hide();
}