Go homepage(回首页) Upload pictures (上传图片) Write articles (发文字帖)
The author:(作者)delvpublished in(发表于) 2014/1/27 6:51:09 如何用C#写一个简单的Login窗口_[Asp.Net教程]
最近,看到网上经常会问如何进行窗口跳转,大多数的问题都是牵扯到Login窗口。其实,在Visual Studio 6以来,比较正确的做法是判断Login窗口的返回值,然后决定是否打开主窗体,那么在C#中也是一样的。
具体做法如下:
首先,创建Login窗口,然后添加相应的输入框和按钮,设置窗口的AcceptButton为窗体的确认按钮,而CancelButton为窗体的取消按钮。例如:
this.AcceptButton = this.btnOK; this.CancelButton = this.btnCancel;
定义确定按钮以及取消按钮事件,如下:
private void btnOK_Click(object sender, System.EventArgs e) { // Here is to use fixed username and password // You can check username and password from DB if( txtUserName.Text == "Admin" && txtPassword.Text == "nopassword" ) { // Save login user info uiLogin.UserName = txtUserName.Text; uiLogin.Password = txtPassword.Text; // Set dialog result with OK this.DialogResult = DialogResult.OK; } else { // Wrong username or password nLoginCount++; if( nLoginCount == MAX_LOGIN_COUNT ) // Over 3 times this.DialogResult = DialogResult.Cancel; else { MessageBox.Show( "Invalid user name and password!" ); txtUserName.Focus(); } } } private void btnCancel_Click(object sender, System.EventArgs e) { // Set dialog result with Cancel this.DialogResult = DialogResult.Cancel; }
然后,在Login窗体的Closing事件中,要进行处理,如下:
private void frmLogin_Closing(object sender, System.ComponentModel.CancelEventArgs e) { // Check whether form is closed with dialog result if( this.DialogResult != DialogResult.Cancel && this.DialogResult != DialogResult.OK ) e.Cancel = true; }
除此外,Login窗体一些辅助代码如下:
private int nLoginCount = 0; private const int MAX_LOGIN_COUNT = 3; private UserInfo uiLogin; public frmLogin( ref UserInfo ui ) { // // Required for Windows Form Designer support // InitializeComponent(); // Set login info to class member uiLogin = ui; }
调用的时候,要修改程序的Main函数,如下:
/// /// The main entry point for the application. /// [STAThread] static void Main() { UserInfo ui = new UserInfo(); frmLogin myLogin = new frmLogin( ref ui ); if( myLogin.ShowDialog() == DialogResult.OK ) { //Open your main form here MessageBox.Show( "Logged in successfully!" ); } else { MessageBox.Show( "Failed to logged in!" ); } }
而附加的UserInfo类如下:
/// /// User info class /// public class UserInfo { private string strUserName; private string strPassword; public string UserName { get{ return strUserName;} set{ strUserName = value; } } public string Password { get{ return strPassword;} set{ strPassword = value;} } public UserInfo() { strUserName = ""; strPassword = ""; } }
赞