如何在WinForms中使用C#从另一个窗体刷新用户控件？

huangapple
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英文:

How To Refresh User Control From Another Form In WinForms Using C#?

问题

我已经尝试了几种方法来实现这个目标。其中一种方法是使用以下代码：

  1. var UserControlee = new UserControl();
  2. UserControlee.load_data();

然而，这实际上什么都没有做。根据我所了解，这是因为我不应该使用窗体的新实例。但是所有建议的方法，比如使用 var UserControlee = new UserControl(this); 都不起作用。

顺便说一下，我通过SQL插入我的数据，目前尝试使用 load() 方法，当在UserControl上使用时，它可以工作并刷新DataGridView。

英文:

I have tried several ways now to achieve this. Amongst other things using this code:

var UserControlee = new UserControl ();
UserControlee .load_data();

this however does literally nothing. From what I have read this is because I should not use a new instance of the form. But all the suggested ways like using var UserControlee = new UserControl (this); don't work.

I by the way insert my data through SQL and currently trie to use the method load(), which works and refreshes the DataGridView when used on UserControl.

答案1

得分: 0

你的问题是关于如何在WinForms中使用C#从另一个窗体刷新用户控件。在你的问题中缺少调试详细信息。尽管如此，一种通用的做法是在需要刷新时，让请求窗体触发一个事件。

以下是一个示例代码，演示了一个名为MainForm的主窗体，其中包含一个用于触发此事件的[Refresh]按钮。主窗体还创建了承载UserControl的第二个窗体。

  1. public partial class MainForm : Form
  2. {
  3.     public MainForm()
  4.     {
  5.         InitializeComponent();
  6.         buttonRefresh.Click += onClickButtonRefresh;
  7.         ucHost = new UserControlHostForm(this);
  8.     }
  9.     UserControlHostForm ucHost;
  10.     protected override void OnLoad(EventArgs e)
  11.     {
  12.         base.OnLoad(e);
  13.         ucHost.StartPosition = FormStartPosition.Manual;
  14.         ucHost.Location = new Point(Location.X + Width + 10, Location.Y);
  15.         ucHost.Show();
  16.     }
  17.     private void onClickButtonRefresh(object? sender, EventArgs e)
  18.     {
  19.         RefreshNeeded?.Invoke(this, EventArgs.Empty);
  20.     }
  21.     public event EventHandler? RefreshNeeded;
  22. }

第二个窗体在其构造方法中订阅了主窗体的事件，并在响应事件时调用了myUserControl.Refresh()。

  1. public partial class UserControlHostForm : Form
  2. {
  3.     public UserControlHostForm(Form owner)
  4.     {
  5.         Owner = owner;
  6.         InitializeComponent();
  8.         // 如果UserControl尚未在设计时添加，请在此处添加。
  9.         myUserControl = new MyUserControl
  10.         {
  11.             BackColor = Color.LightBlue,
  12.             Dock = DockStyle.Fill,
  13.         };
  14.         Controls.Add(myUserControl);
  16.         // 订阅主窗体事件
  17.         ((MainForm)Owner).RefreshNeeded += onRefreshNeeded;
  18.     }
  19.     MyUserControl myUserControl;
  20.     private void onRefreshNeeded(object? sender, EventArgs e)
  21.     {
  22.         myUserControl.Refresh();
  23.         Visible = true;
  24.     }
  25.     protected override void OnFormClosing(FormClosingEventArgs e)
  26.     {
  27.         base.OnFormClosing(e);
  28.         if (e.CloseReason.Equals(CloseReason.UserClosing))
  29.         {
  30.             e.Cancel = true;
  31.             Hide();
  32.         }
  33.     }
  34. }

自定义的UserControl以应用程序特定的方式实现了Control.Refresh()方法，例如通过调用load()。以下是一个模拟实现，演示了它是如何工作的。

  1. class MyUserControl : UserControl
  2. {
  3.     public MyUserControl()
  4.     {
  5.         Controls.Add(label);
  6.     }
  7.     public new void Refresh()
  8.     {
  9.         base.Refresh();
  10.         load();
  11.     }
  12.     Label label = new Label { Location = new Point(10, 100), AutoSize = true,  };
  13.     int debugCount = 0;
  14.     private void load()
  15.     {
  16.         label.Text =  $"Count = {++debugCount}: 你的自定义SQL加载代码在这里";
  17.     }
  18. }

这些代码组成了一个简单的示例，演示了如何从一个窗体刷新另一个窗体中的用户控件。

英文:

Your question is How To Refresh User Control From Another Form In WinForms Using C#. The debugging details are missing in your question. Nevertheless, a general answer for one way of doing that is to have the requesting form fire an event when a refresh is needed.

Here is a minimal example of a MainForm that features a [Refresh] button to test fire this event. The main form also creates the second form that hosts the UserControl.

如何在WinForms中使用C#从另一个窗体刷新用户控件？

  1. public partial class MainForm : Form
  2. {
  3.     public MainForm()
  4.     {
  5.         InitializeComponent();
  6.         buttonRefresh.Click += onClickButtonRefresh;
  7.         ucHost = new UserControlHostForm(this);
  8.     }
  9.     UserControlHostForm ucHost;
  10.     protected override void OnLoad(EventArgs e)
  11.     {
  12.         base.OnLoad(e);
  13.         ucHost.StartPosition = FormStartPosition.Manual;
  14.         ucHost.Location = new Point(Location.X + Width + 10, Location.Y);
  15.         ucHost.Show();
  16.     }
  17.     private void onClickButtonRefresh(object? sender, EventArgs e)
  18.     {
  19.         RefreshNeeded?.Invoke(this, EventArgs.Empty);
  20.     }
  21.     public event EventHandler? RefreshNeeded;
  22. }

The second form subscribes to the main form event in its constructor method and calls myUserControl.Refresh() in response.

  1. public partial class UserControlHostForm : Form
  2. {
  3.     public UserControlHostForm(Form owner)
  4.     {
  5.         Owner = owner;
  6.         InitializeComponent();
  8.         // If the UserControl hasn't already been
  9.         // added in the Designer, add it here.
  10.         myUserControl = new MyUserControl
  11.         {
  12.             BackColor = Color.LightBlue,
  13.             Dock = DockStyle.Fill,
  14.         };
  15.         Controls.Add(myUserControl);
  17.         // Subscribe to the MainForm event
  18.         ((MainForm)Owner).RefreshNeeded += onRefreshNeeded;
  19.     }
  20.     MyUserControl myUserControl;
  21.     private void onRefreshNeeded(object? sender, EventArgs e)
  22.     {
  23.         myUserControl.Refresh();
  24.         Visible = true;
  25.     }
  26.     protected override void OnFormClosing(FormClosingEventArgs e)
  27.     {
  28.         base.OnFormClosing(e);
  29.         if (e.CloseReason.Equals(CloseReason.UserClosing))
  30.         {
  31.             e.Cancel = true;
  32.             Hide();
  33.         }
  34.     }
  35. }

The custom UserControl implements the Control.Refresh() method in an app-specific manner, for example by calling load(). Here is a mock implementation that demonstrates that it's working.

  1. class MyUserControl : UserControl
  2. {
  3.     public MyUserControl()
  4.     {
  5.         Controls.Add(label);
  6.     }
  7.     public new void Refresh()
  8.     {
  9.         base.Refresh();
  10.         load();
  11.     }
  12.     Label label = new Label { Location = new Point(10, 100), AutoSize = true,  };
  13.     int debugCount = 0;
  14.     private void load()
  15.     {
  16.         label.Text =  $"Count = {++debugCount}: Your custom SQL load code goes here";
  17.     }
  18. }

huangapple
  • 本文由 发表于 2023年1月8日 22:42:14
  • 转载请务必保留本文链接：https://go.coder-hub.com/75048648.html
  • c#
  • winforms
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