C # form (Login interface)

First drag a lable (write user name) followed by a Textbox

Then lable( write password ) followed by a TextBox (need to set properties - behavior -Usesystempasswordchar( The default password is black ))

Plus button (text login)

Such as:

1, Properties--Miscellaneous (AcceptButton set to Button1) can press ENTER to display the next page

2, the value: login.cs[design] to main.cs[design] a value in the construction method: 1, in the main.cs[design] Drag a lable to prepare to receive

And then reload a method in the Main.cs:

Again in the Login.cs to receive:--Build the main form object when main m=new main (UID)

Double-click Login plus an event:

The data manipulation classes are as follows:

public partial class Login:form
{
public string Username;
Public Login ()
{
InitializeComponent ();
}

private void Button1_Click (object sender, EventArgs e)
{
First remove the username and password
Define variables to take to user name, password
String uid= textuid. Text;
String pwd= textpwd. Text;
And then judge if the UID is empty.
if (uid! = "" && pwd! = "")
{
Don't judge if the UID pwd is a match.
Manipulating databases to do three of classes

Loginda da = new Loginda (); create an object before calling the method
Da.                      Denglu (UID,PWD); call the method in the third class and pass two arguments.
if (DA. Denglu (UID, pwd)) judgment
{

After logging in, close the login page, display only the main page, main becomes the main form
Assigning a user name to a member variable username
Username = UID;
change the return value of the form to OK three steps
This. DialogResult = DialogResult.OK;
Close the form
This. Close ();
}
Else
{
MessageBox.Show ("User name or password is wrong! ");
}

}

Else
{
If it is empty
MessageBox.Show ("User name and password cannot be empty!") ");
}

}

Changes required: Program.cs

Drop-down list:

public partial class Main:form
{

Private Zgda CDA;
Public Main ()
{
InitializeComponent ();
}
Public main (string username)//overloaded with a Main method
{

InitializeComponent ();

CDA = new Zgda ();

}

private void Label1_click (object sender, EventArgs e)
{

}

private void Main_load (object sender, EventArgs e)
{

Populate the province's drop-down list
Fillsheng ();
Fill City drop-down list
Fillshi ();
Drop-down list of populated areas
Fillqu ();
}

private void Cmbsheng_selectedindexchanged (object sender, EventArgs e)

{
Fill City drop-down list
Fillshi ();

}

private void Cmbshi_selectedindexchanged (object sender, EventArgs e)
{
Drop-down list of populated areas
Fillqu ();
}
public void Fillsheng ()//method of filling Province
{
list<zg> list= cda.select ("0001");A collection of all the subsets under that parent that are traced to the parent code
Cmbsheng. DataSource = List;Give the found collection to the province's dropdown as a data source
Cmbsheng. DisplayMember = "Name";Show national Names
Cmbsheng. ValueMember = "Code";background values are national codes .
}
public void Fillshi ()methods of filling the city
{
list<zg> List = Cda.select (Cmbsheng. Selectedvalue.tostring ());Select which province to take the code of which province
Cmbshi. DataSource = List;send the found collection to the city's dropdown as a data source
Cmbshi. DisplayMember = "Name";Show national Names
Cmbshi. ValueMember = "Code";background values are national codes .
}
public void Fillqu ()//method of filling the city
{
list<zg> List = Cda.select (Cmbshi. Selectedvalue.tostring ());Select which province to take the code of which province
Cmbqu. DataSource = List;send the found collection to the city's dropdown as a data source
Cmbqu. DisplayMember = "Name";Show national Names
Cmbqu. ValueMember = "Code";background values are national codes .
}
}
}

C # form (Login interface)