How do I Close a Login form and Open the Mainform

private void okBtn_Click(object sender, EventArgs e)
{
    system.data.SqlClient.Sqlconnection oConn = new SqlConnection(UserInformationConnectionString);
    system.data.SqlClient.Sqlcommand oComm = new SqlCommand();

    oComm.CommandType = CommandType.StoredProcedure;
    oComm.CommandText = "LOGIN";

    SqlParameter idParam = new SqlParameter("@Username", string);
    idParam.Value = idtextbox.Text;

    SqlParameter PassParam = new SqlParameter("@Password", string);
    idParam.Value = idtextbox.Text;

    SqlCommand.Paramters.Add(idParam);
    SqlCommand.Paramters.Add(PassParam);
   
    try
    {
        oConn.Open();
        int indice = oComm.ExecuteNonQuery();
       
        if(indice!=0) Form1.Show();
       
        if(indice==0)MessageBox.Show("Login failed");
    }
   
    finally
    {
        oConn.Close();
    }
   
}

This is the problem with the code:

SqlParameter idParam = new SqlParameter("@Username", string);
idParam.Value = idtextbox.Text;

SqlParameter PassParam = new SqlParameter("@Password", string);
idParam.Value = idtextbox.Text;

you passed string as an argument in the SqlParameter constructor instead of putting the value of the field.

It should be:

SqlParameter idParam = new SqlParameter("@Username", idtextbox.Text);
//idParam.Value = idtextbox.Text;
SqlParameter PassParam = new SqlParameter("@Password", idtextbox.Text);
//idParam.Value = idtextbox.Text;

note: for the PassParam, I think you should have something like passtextbox.Text as argument

OK

Thanks you I would take a look.

Dallr

you know something when I migrate from the previous Microsoft technology to the .Net one, this was my first problem ha ha ha, It was horrible, I was about to leave .Net to windev because of this problem ha ha ha, you make me remember  those days ha ha ha!!!
But now it's pretty ok with the .Net, but never the less you see this piece of code It could be very useful for you you know? even with a web context but with some rectifications
By the way, I invite you to take a look on my blog listed bellow the blogspot one, there are many useful code there, in addition, I writted a sort of revision of the .Net framework very useful for someone who wants to understand the .Net framework and pass the certification exam

Not at all, you're welcome

I found this comment on the internet and it seems to be working.
http://bytes.com/forum/thread443767.html

Thanks for your assistance

Thanks for the detailed explanation. It looks like you have placed a lot of time into helping me. However, I really just want to know "how to close a form and open another by the click of a button" i.e close the form that the button is on , then open a new different form.?

From you code it looks like you are doing this via this line   if(indice!=0) yourMainForm.Show();.
I am not getting the method myMainForm.Show() when i use the above.

Regards,
Dane

First, suppose that you store data about you users in an sql server data base in a given data table
 So create a procedure that verify the existance of the user

CREATE PROCEDURE LOGIN
(
     @UserID as nvarchar(50),
     @Password as nvarchar(50)
)
 
SELECT User,Password FROM User WHERE User=@UserID AND Password = @Password

GO

then create a login page with two text boxes and two button login and cancel
 implement the code of the login button as follow

public void login_click(.......)
{
     system.data.SqlClient.Sqlconnection oConn = new SqlConnection(/*your connection string here*/);
    system.data.SqlClient.Sqlcommand  oComm = new SqlCommand();
    oComm.CommandType = CommandType.StoredProcedure;
    oComm.CommandText = "LOGIN";
    SqlParameter idParam = new SqlParameter("@UserID", string);
    idParam.Value = idtextbox.Text;
    SqlParameter PassParam = new SqlParameter("@Password", string);
    idParam.Value = idtextbox.Text;
    SqlCommand.Paramters.Add(idParam);
   SqlCommand.Paramters.Add(PassParam);
   try
   {
        oConn.Open();
        int indice = oComm.ExecuteNonQuery();
        if(indice!=0) yourMainForm.Show();
        if(indice==0)MessageBox.Show("Login failed");
       
   }
   finally
   {
        oConn.Close();
   }
}

implement the Cancel button

public void Cancel_Click(...)
{
     Application.Exit();
}

go to the program.cs and set Application.Run(yourLoginPage...) instead of the default form1 page