类变量在类实例化后重置
本文关键字：实例化 类变量 | 更新日期: 2023-09-27 18:21:08
所以我正在编写一个应用程序，它有一个登录屏幕和一个菜单屏幕。
菜单为每个级别的用户启用了不同的按钮。为了在用户登录时做到这一点，会分配一个int，让应用程序知道用户登录的级别以及要启用的按钮/报告。
我遇到的问题是，当关闭报告并再次调用菜单时，变量会重置回默认的管理级别。
Menu M = new Menu(Permission);
M.Show();
this.Hide();
此代码用于从登录中调出菜单，int正被传递给构造函数。
public Menu(string Permission)
{
InitializeComponent();
AccessLevel = int.Parse(Permission);
LockKeys();
}
public Menu()
{
InitializeComponent();
LockKeys();
}
现在，这是将int赋值给类变量的菜单代码。
我有10个不同的报告，当我按下报告的返回键时，这就是我调用菜单的方式。
Menu shwMenu = new Menu();
shwMenu.Show();
this.Hide();
现在我明白了问题是它调用的构造函数没有分配变量。现在，我所能想到的就是将变量反弹到每个报告并返回，只需调用正确的构造函数。
我的问题是，有更简单的方法吗？保存类变量的某种方法，这样我就不必每次调用类时都重新实例化它。
public partial class Menu : Form
{
private int AccessLevel;
public Menu(string Permission)
{
InitializeComponent();
AccessLevel = int.Parse(Permission);
LockKeys();
}
public Menu()
{
InitializeComponent();
LockKeys();
}
private void LockKeys()
{
if(AccessLevel == 1)
{
btnSR.Enabled = false;
btnVSC.Enabled = false;
btnPT.Enabled = false;
btnCT.Enabled = false;
btnTS.Enabled = false;
btnBookJob.Enabled = false;
btnCompJob.Enabled = false;
btnCompServ.Enabled = false;
btnVS.Enabled = true;
}
else if (AccessLevel == 2)
{
btnSR.Enabled = false;
btnVSC.Enabled = false;
btnPT.Enabled = false;
btnCT.Enabled = false;
btnTS.Enabled = false;
btnBookJob.Enabled = true;
btnCompJob.Enabled = true;
btnCompServ.Enabled = false;
btnVS.Enabled = false;
}
else if (AccessLevel == 3)
{
btnSR.Enabled = false;
btnVSC.Enabled = false;
btnPT.Enabled = false;
btnCT.Enabled = false;
btnTS.Enabled = false;
btnBookJob.Enabled = true;
btnCompJob.Enabled = false;
btnCompServ.Enabled = true;
btnVS.Enabled = false;
}
else if (AccessLevel == 4)
{
btnSR.Enabled = false;
btnVSC.Enabled = false;
btnPT.Enabled = false;
btnCT.Enabled = false;
btnTS.Enabled = true;
btnBookJob.Enabled = false;
btnCompJob.Enabled = false;
btnCompServ.Enabled = false;
btnVS.Enabled = false;
}
}
private void btnVS_Click(object sender, EventArgs e)
{
VehicleStatR1 VS = new VehicleStatR1();
VS.Show();
this.Hide();
}
private void btnSR_Click(object sender, EventArgs e)
{
ServRequireR3 SR = new ServRequireR3();
SR.Show();
this.Hide();
}
private void btnVSC_Click(object sender, EventArgs e)
{
VehServCompleteR4 VSC = new VehServCompleteR4();
VSC.Show();
this.Hide();
}
private void btnPT_Click(object sender, EventArgs e)
{
PlannedTripR6 PT = new PlannedTripR6();
PT.Show();
this.Hide();
}
private void btnCT_Click(object sender, EventArgs e)
{
ActualTripR7 CT = new ActualTripR7();
CT.Show();
this.Hide();
}
private void btnTS_Click(object sender, EventArgs e)
{
HoursWorkedR8 TS = new HoursWorkedR8();
TS.Show();
this.Hide();
}
private void btnBookJob_Click(object sender, EventArgs e)
{
BookJobServ BJ = new BookJobServ();
BJ.Show();
this.Hide();
}
private void btnCompJob_Click(object sender, EventArgs e)
{
CompJob CJ = new CompJob();
CJ.Show();
this.Hide();
}
private void btnCompServ_Click(object sender, EventArgs e)
{
CompServ CS = new CompServ();
CS.Show();
this.Hide();
}
private void btnLogOut_Click(object sender, EventArgs e)
{
LogIn LI = new LogIn();
this.Hide();
LI.Show();
}
private void btnExit_Click(object sender, EventArgs e)
{
Application.Exit();
}
}
这是菜单类，我一直在回溯，但AccessLevel变量更改为默认值。
感谢
我认为您正在寻找的是一个"静态"变量，它是一个类级变量。
private static int AccessLevel;
静态变量是在类级别中定义的，类的所有实例都可以访问和修改它们。换句话说，静态变量在类实例之间共享。更多信息：https://msdn.microsoft.com/en-us/library/98f28cdx.aspx?f=255&MSPP错误=-2147217396
另一种选择是使用一个静态类来保存您需要的所有信息，例如：
public static class CurrentUser
{
public static string UserName { get; set; }
public static int AccessLevel { get; set; }
}
用户登录时使用的：
public void LogUserIn(string userName, string password)
{
//Make sure to reset, so an invalid login doesn't retain data
LogUserOut();
//Do the user validation here
CurrentUser.UserName = userName;
CurrentUser.AccessLevel = 0; //whatever was read from your user database
}
public void LogUserOut()
{
CurrentUser.UserName = "";
CurrentUser.AccessLevel = int.MinValue;
}
然后，当你需要使用访问级别时，你不需要担心传递值，例如，你的菜单表单会是这样的：
public partial class Menu : Form
{
public Menu()
{
InitializeComponent();
LockKeys();
}
private void LockKeys()
{
if(CurrentUser.AccessLevel == 1)
{
//Enable/Disable Controls
}
else if (CurrentUser.AccessLevel == 2)
{
//Enable/Disable Controls
}
else if (CurrentUser.AccessLevel == 3)
{
//Enable/Disable Controls
}
else if (CurrentUser.AccessLevel == 4)
{
//Enable/Disable Controls
}
}
}
附带说明一下，为了避免代码重复并提高安全性，您应该创建初始化函数LockKeys，如下所示：
private void LockKeys()
{
//Set them all default false, and then only enable.
btnSR.Enabled = false;
btnVSC.Enabled = false;
btnPT.Enabled = false;
btnCT.Enabled = false;
btnTS.Enabled = false;
btnBookJob.Enabled = false;
btnCompJob.Enabled = false;
btnCompServ.Enabled = false;
btnVS.Enabled = false;
if(AccessLevel == 1)
{
btnVS.Enabled = true;
}
else if (AccessLevel == 2)
{
btnBookJob.Enabled = true;
btnCompJob.Enabled = true;
}
else if (AccessLevel == 3)
{
btnBookJob.Enabled = true;
btnCompServ.Enabled = true;
}
else if (AccessLevel == 4)
{
btnTS.Enabled = true;
}
}