C＃验证Winforms上文本框的输入 [英] C# Validating input for textbox on winforms

问题描述

我想先检查用户在文本框中写的内容，然后再将其保存到数据库中。做这个的最好方式是什么？我想我总是可以写一些if或try-catch块，但是我想知道是否有更好的方法。我已经阅读了有关验证事件的内容，但不确定如何使用它们。

解决方案

说明

有很多方法可以验证TextBox。您可以在以后每次击键或 Validating 事件中执行此操作。

<$>如果TextBox失去焦点，则会触发c $ c> Validating 事件。例如，当用户单击另一个控件时。如果您设置的 e.Cancel = true ，则TextBox不会失去焦点。

MSDN-Control.Validating事件当您使用键盘（TAB，SHIFT + TAB等），调用Select或SelectNextControl方法或设置ContainerControl来更改焦点时。 ActiveControl属性为当前形式，焦点事件按以下顺序发生

Enter

GotFocus

离开

确认

确认

LostFocus

使用鼠标或调用Focus方法更改焦点时，焦点事件按以下顺序发生： / p>

输入

GotFocus

LostFocus

离开

验证

验证

示例验证事件

  private void textBox1_Validating（对象发送者，CancelEventArgs e）
 {
 if（textBox1.Text！= something）
 e.Cancel = true; 
} 
  

更新

您可以使用 ErrorProvider 来可视化您的TextBox无效。
检出在Windows窗体和C＃中使用错误提供程序控件

更多信息

• MSDN-Control.Validating事件


• MSDN-ErrorProvider组件（Windows窗体）


• 在Windows窗体和C＃中使用错误提供程序控件

I want to check what the user is writing in a textbox before I save it in a database. What is the best way to do this? I guess I can always write some ifs or some try-catch blocks, but I was wondering if there's a better method. I've read something about Validating Events, but I am not sure how can I use them.

解决方案

Description

There are many ways to validate your TextBox. You can do this on every keystroke, at a later time, or on the Validating event.

The Validating event gets fired if your TextBox looses focus. When the user clicks on a other Control, for example. If your set e.Cancel = true the TextBox doesn't lose the focus.

MSDN - Control.Validating Event When you change the focus by using the keyboard (TAB, SHIFT+TAB, and so on), by calling the Select or SelectNextControl methods, or by setting the ContainerControl.ActiveControl property to the current form, focus events occur in the following order

Enter

GotFocus

Leave

Validating

Validated

LostFocus

When you change the focus by using the mouse or by calling the Focus method, focus events occur in the following order:

Enter

GotFocus

LostFocus

Leave

Validating

Validated

Sample Validating Event

private void textBox1_Validating(object sender, CancelEventArgs e)
{
    if (textBox1.Text != "something")
        e.Cancel = true;
}

Update

You can use the ErrorProvider to visualize that your TextBox is not valid. Check out Using Error Provider Control in Windows Forms and C#

More Information

• MSDN - Control.Validating Event
• MSDN - ErrorProvider Component (Windows Forms)
• Using Error Provider Control in Windows Forms and C#

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