blocks|key|3111107|text|private+void+_txtPath_KeyDown(object+sender,+KeyEventArgs+e)
++{
+++++if+((e.Key+<+Key.A)+%7C%7C+(e.Key+>+Key.Z))
++++++++e.Handled+=+true;
++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3111108|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>private void _txtPath_KeyDown(object sender, KeyEventArgs e)
 {
 if ((e.Key &lt; Key.A) || (e.Key &gt; Key.Z))
 e.Handled = true;
 }
</code></pre>

blocks|key|3324022|text|处理KeyDown或KeyPress事件是实现此目的的一种方法，但是程序员通常会忘记，用户仍然可以将无效文本复制粘贴到文本框中。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3324023|一种更好的方法是处理TextChanged事件，并去掉那里的任何有问题的字符。这有点复杂，因为您必须跟踪插入符号的位置，并在更改框的Text属性后将其重新设置到适当的位置。|3324024|根据您的应用程序的需要，我只需要让用户输入他们想要的内容，然后在用户尝试提交时标记文本框(将文本变为红色或其他什么)。|3324025|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

Handling the KeyDown or KeyPress events is one way to do this, but programmers usually forget that a user can still copy-and-paste invalid text into the textbox.

A somewhat better way is to handle the TextChanged event, and strip out any offending characters there. This is a bit more complicated, as you have to keep track of the caret position and re-set it to the appropriate spot after changing the box's Text property.

Depending on your application's needs, I would just let the user type in whatever they want, and then flag the textbox (turn the text red or something) when the user tries to submit.

blocks|key|339354|text|我只想为那些通过搜索结束的人添加一些代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|339355|private+void+Filter_TextChanged(object+sender,+EventArgs+e)
{
++++var+textboxSender+=+(TextBox)sender;
++++var+cursorPosition+=+textboxSender.SelectionStart;
++++textboxSender.Text+=+Regex.Replace(textboxSender.Text,+"[%5E0-9a-zA-Z+]",+"");
++++textboxSender.SelectionStart+=+cursorPosition;
}|code-block|syntax|javascript|339356|这是一个更改过滤器，因此可以处理复制和粘贴，并保留光标位置，以便在中间更改文本正常工作。|339357|注意，它使用'sender‘来获取控件名称，允许这一个函数链接到多个文本框，假设它们需要相同的过滤器。您可以通过转到控件的事件部分并手动选择TextChanged事件的函数来链接多个控件。|339358|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Just wanted to add some code for those ending up here by search:

<pre><code>private void Filter_TextChanged(object sender, EventArgs e)
{
 var textboxSender = (TextBox)sender;
 var cursorPosition = textboxSender.SelectionStart;
 textboxSender.Text = Regex.Replace(textboxSender.Text, "[^0-9a-zA-Z ]", "");
 textboxSender.SelectionStart = cursorPosition;
}
</code></pre>

This is a change filter, so handles copy and paste, and preserves cursor position so that changing text in the middle works properly.

Note it uses the 'sender' to get the control name, allowing this one function to be linked to multiple textbox boxes, assuming they need the same filter. You can link multiple controls by going to the event section of a control and manually picking the function for the TextChanged event.

blocks|key|3323996|text|使用正则表达式过滤掉其他字符。或者使用Char.IsDigit、IsXXX方法过滤掉不需要的字符。有很多方法可以做到这一点。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3323997|更新:如果您必须使用KeyDown，那么您似乎还需要处理KeyPressed，并将obEventArgs.Handled+=+true设置为禁止字符。请参阅KeyDown+MSDN+Page上的示例|offset|length|3323998|更新:现在你指定它是WPF了。下面的代码将只允许a-z和A-Z字符输入到文本框中。根据需要扩展...|3323999|private+void+_txtPath_KeyDown(object+sender,+KeyEventArgs+e)
++++++{
+++++++++if+((e.Key+<+Key.A)+%7C%7C+(e.Key+>+Key.Z))
++++++++++++e.Handled+=+true;
++++++}|code-block|syntax|javascript|3324000|如果你将内容复制粘贴到文本框中，这将会崩溃。在用户离开控件或单击OK/Submit时验证整个文本，就像MusicGenesis所说的那样。|3324001|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/system.windows.forms.control.keydown.aspx^0|0|26|H|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@$D|Y|E|Z|1|10]]|A|$]]|$1|F|3|G|5|6|7|11|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|12|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

Use a regex to filter out the other characters. Or use Char.IsDigit, IsXXX methods to filter out unwanted characters. Lots of ways to do this.

Update: If you must use KeyDown then it seems that you need to also handle KeyPressed and set obEventArgs.Handled = true to disallow the characters. See the example on the <a href="http://msdn.microsoft.com/en-us/library/system.windows.forms.control.keydown.aspx" rel="noreferrer">KeyDown MSDN Page</a> 

Update: Now that you specify it's WPF. The below code will allow only a-z and A-Z characters to be entered into the textbox. Extend as needed...

<pre><code>private void _txtPath_KeyDown(object sender, KeyEventArgs e)
 {
 if ((e.Key &lt; Key.A) || (e.Key &gt; Key.Z))
 e.Handled = true;
 }
</code></pre>

This will break if you copy-paste stuff into the text-box. Validate the entire text once the user leaves the control or when he clicks OK/Submit as MusicGenesis says.

blocks|key|340639|text|我认为值得考虑对TextBox的TextChanged事件进行过滤。您可以创建一个操作来删除文本字符串中的任何无效字符。这比阻塞KeyDown事件要麻烦一些。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|340640|但是，我认为这是可行的方法，因为您没有阻止WPF内置的KeyDown/Up事件处理机制，因此复制/粘贴仍然有效。您将在更高的抽象级别上工作，因此我认为更容易弄清楚发生了什么。|340641|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

I think it's worth considering doing the filtering on the TextBox's TextChanged event. You can create an operation that gets rid of any non-valid characters from your text string. This is a bit more messy than blocking the KeyDown event.

But, I think this is the way to go because you are not blocking WPF's built-in KeyDown/Up event handling mechanisms, so copy/paste still works. You would be working at a higher level of abstractions so I think it will be easier to figure out what is going on.

blocks|key|340690|text|我在silverlight中遇到了这个，并写了类似这样的东西。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|340691|private+string+_filterRegexPattern+=+"[%5Ea-zA-Z0-9]";+//+This+would+be+"[%5Ea-z0-9+]"+for+this+question.
private+int+_stringMaxLength+=+24;


private+void+_inputTextBox_TextChanged(object+sender,+TextChangedEventArgs+e)
{
++++if+(!string.IsNullOrEmpty(_filterRegexPattern))
++++{
++++++++var+text+=+_inputTextBox.Text;
++++++++var+newText+=+Regex.Replace(_inputTextBox.Text,+_filterRegexPattern,+"");

++++++++if+(newText.Length+>+_stringMaxLength)
++++++++{
++++++++++++newText+=+newText.Substring(0,+_stringMaxLength);
++++++++}


++++++++if+(text.Length+!=+newText.Length)
++++++++{
++++++++++++var+selectionStart+=+_inputTextBox.SelectionStart+-+(text.Length+-+newText.Length);
++++++++++++_inputTextBox.Text+=+newText;
++++++++++++_inputTextBox.SelectionStart+=+selectionStart;
++++++++}
++++}
}|code-block|syntax|javascript|340692|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I ran into this in silverlight and wrote something like this.

<pre><code>private string _filterRegexPattern = "[^a-zA-Z0-9]"; // This would be "[^a-z0-9 ]" for this question.
private int _stringMaxLength = 24;


private void _inputTextBox_TextChanged(object sender, TextChangedEventArgs e)
{
 if (!string.IsNullOrEmpty(_filterRegexPattern))
 {
 var text = _inputTextBox.Text;
 var newText = Regex.Replace(_inputTextBox.Text, _filterRegexPattern, "");

 if (newText.Length &gt; _stringMaxLength)
 {
 newText = newText.Substring(0, _stringMaxLength);
 }


 if (text.Length != newText.Length)
 {
 var selectionStart = _inputTextBox.SelectionStart - (text.Length - newText.Length);
 _inputTextBox.Text = newText;
 _inputTextBox.SelectionStart = selectionStart;
 }
 }
}
</code></pre>

blocks|key|3111257|text|我用一个自定义的依赖属性来实现这一点。它可重用于任何TextBox控件，使用起来比构建键事件快得多、效率高得多，并且使我的代码文件更加整洁。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3111258|此外，它还可以处理其他不触发按键事件的输入方法，例如使用鼠标将值粘贴到TextBox中。|3111259|自定义DP的代码如下所示：|3111260|//+When+set+to+a+Regex,+the+TextBox+will+only+accept+characters+that+match+the+RegEx

///+<summary>
///+Lets+you+enter+a+RegexPattern+of+what+characters+are+allowed+as+input+in+a+TextBox
///+</summary>
public+static+readonly+DependencyProperty+AllowedCharactersRegexProperty+=
++++DependencyProperty.RegisterAttached("AllowedCharactersRegex",
++++++++++++++++++++++++++++++++++++++++typeof(string),+typeof(TextBoxProperties),
++++++++++++++++++++++++++++++++++++++++new+UIPropertyMetadata(null,+AllowedCharactersRegexChanged));

//+Get
public+static+string+GetAllowedCharactersRegex(DependencyObject+obj)
{
++++return+(string)obj.GetValue(AllowedCharactersRegexProperty);
}

//+Set
public+static+void+SetAllowedCharactersRegex(DependencyObject+obj,+string+value)
{
++++obj.SetValue(AllowedCharactersRegexProperty,+value);
}

//+Events
public+static+void+AllowedCharactersRegexChanged(DependencyObject+obj,+DependencyPropertyChangedEventArgs+e)
{
++++var+tb+=+obj+as+TextBox;
++++if+(tb+!=+null)
++++{
++++++++if+(e.NewValue+!=+null)
++++++++{
++++++++++++tb.PreviewTextInput+%2B=+Textbox_PreviewTextChanged;
++++++++++++DataObject.AddPastingHandler(tb,+TextBox_OnPaste);
++++++++}
++++++++else
++++++++{
++++++++++++tb.PreviewTextInput+-=+Textbox_PreviewTextChanged;
++++++++++++DataObject.RemovePastingHandler(tb,+TextBox_OnPaste);
++++++++}
++++}
}

public+static+void+TextBox_OnPaste(object+sender,+DataObjectPastingEventArgs+e)
{
++++var+tb+=+sender+as+TextBox;

++++bool+isText+=+e.SourceDataObject.GetDataPresent(DataFormats.Text,+true);
++++if+(!isText)+return;

++++var+newText+=+e.SourceDataObject.GetData(DataFormats.Text)+as+string;
++++string+re+=+GetAllowedCharactersRegex(tb);
++++re+=+string.Format("[%5E{0}]",+re);

++++if+(Regex.IsMatch(newText.Trim(),+re,+RegexOptions.IgnoreCase))
++++{
++++++++e.CancelCommand();
++++}
}

public+static+void+Textbox_PreviewTextChanged(object+sender,+TextCompositionEventArgs+e)
{
++++var+tb+=+sender+as+TextBox;
++++if+(tb+!=+null)
++++{
++++++++string+re+=+GetAllowedCharactersRegex(tb);
++++++++re+=+string.Format("[%5E{0}]",+re);

++++++++if+(Regex.IsMatch(e.Text,+re,+RegexOptions.IgnoreCase))
++++++++{
++++++++++++e.Handled+=+true;
++++++++}
++++}
}|code-block|syntax|javascript|3111261|它的用法如下：|3111262|<TextBox+Text="{Binding+SomeValue,+UpdateSourceTrigger=PropertyChanged}"+
+++++++++local:TextBoxHelpers.AllowedCharactersRegex="a-zA-Z0-9\s"+/>|3111263|entityMap^0|Q|7|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|Y|8|@]|D|@]|E|$]]|$1|J|3|K|5|L|7|Z|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|6|7|10|8|@]|D|@]|E|$]]|$1|Q|3|R|5|L|7|11|8|@]|D|@]|E|$M|N]]|$1|S|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|T|$]]

I accomplish this with a custom Dependency Property. It's reusable for any <code>TextBox</code> control, is much faster and more efficient to use than building key events, and makes my code files much cleaner.

In addition, it can handle other input methods which does not trigger key events, such as pasting a value into the TextBox using the mouse.

The code for the custom DP looks like this:

<pre><code>// When set to a Regex, the TextBox will only accept characters that match the RegEx

/// &lt;summary&gt;
/// Lets you enter a RegexPattern of what characters are allowed as input in a TextBox
/// &lt;/summary&gt;
public static readonly DependencyProperty AllowedCharactersRegexProperty =
 DependencyProperty.RegisterAttached("AllowedCharactersRegex",
 typeof(string), typeof(TextBoxProperties),
 new UIPropertyMetadata(null, AllowedCharactersRegexChanged));

// Get
public static string GetAllowedCharactersRegex(DependencyObject obj)
{
 return (string)obj.GetValue(AllowedCharactersRegexProperty);
}

// Set
public static void SetAllowedCharactersRegex(DependencyObject obj, string value)
{
 obj.SetValue(AllowedCharactersRegexProperty, value);
}

// Events
public static void AllowedCharactersRegexChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
 var tb = obj as TextBox;
 if (tb != null)
 {
 if (e.NewValue != null)
 {
 tb.PreviewTextInput += Textbox_PreviewTextChanged;
 DataObject.AddPastingHandler(tb, TextBox_OnPaste);
 }
 else
 {
 tb.PreviewTextInput -= Textbox_PreviewTextChanged;
 DataObject.RemovePastingHandler(tb, TextBox_OnPaste);
 }
 }
}

public static void TextBox_OnPaste(object sender, DataObjectPastingEventArgs e)
{
 var tb = sender as TextBox;

 bool isText = e.SourceDataObject.GetDataPresent(DataFormats.Text, true);
 if (!isText) return;

 var newText = e.SourceDataObject.GetData(DataFormats.Text) as string;
 string re = GetAllowedCharactersRegex(tb);
 re = string.Format("[^{0}]", re);

 if (Regex.IsMatch(newText.Trim(), re, RegexOptions.IgnoreCase))
 {
 e.CancelCommand();
 }
}

public static void Textbox_PreviewTextChanged(object sender, TextCompositionEventArgs e)
{
 var tb = sender as TextBox;
 if (tb != null)
 {
 string re = GetAllowedCharactersRegex(tb);
 re = string.Format("[^{0}]", re);

 if (Regex.IsMatch(e.Text, re, RegexOptions.IgnoreCase))
 {
 e.Handled = true;
 }
 }
}
</code></pre>

And it's used like this:

<pre><code>&lt;TextBox Text="{Binding SomeValue, UpdateSourceTrigger=PropertyChanged}" 
 local:TextBoxHelpers.AllowedCharactersRegex="a-zA-Z0-9\s" /&gt;
</code></pre>

blocks|key|3324059|text|我知道winForms提供了一个MaskedTextBox控件，它可以让您准确地指定这类事情。我不知道WPF，所以我不知道它是否在那里，但如果它是，就去做吧。这比所有这些按键和事件要容易得多，也更健壮。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3324060|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I know that winForms have available a MaskedTextBox control, which lets you specify exactly this sort of thing. I don't know WPF, so I dunno if that's available there, but if it is, do that. Its MUCH easier than all this stuff with keypresses and events, and more robust too.

blocks|key|341743|text|要做到这一点，最简单的方法是包含扩展的WPF工具包，它有一个控件，可以通过指定掩码来精确地执行您所要求的操作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|341744|http://wpftoolkit.codeplex.com/wikipage?title=MaskedTextBox&referringTitle=Home|offset|length|341745|如果需要，它还会在您输入时在文本框中显示掩码。|341746|(它还有许多其他有用的控件)|341747|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|27|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@$D|S|E|T|1|U]]|A|$]]|$1|F|3|G|5|6|7|V|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|W|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|C]]]]

The easiest way to do this would be to included the Extended WPF Toolkit which has a control for doing exactly what you are asking for by specifying a mask.

<a href="http://wpftoolkit.codeplex.com/wikipage?title=MaskedTextBox&amp;referringTitle=Home" rel="nofollow">http://wpftoolkit.codeplex.com/wikipage?title=MaskedTextBox&amp;referringTitle=Home</a>

It will also display the mask in the text box as you are inputting if required.

(It also has many other useful controls)

blocks|key|3324048|text|您的regExp可能看起来像0-9a-zA-Z*，只允许英文字母数字字符|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3324049|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

and your regExp could look like [0-9a-zA-Z]* to allow only English alphanumeric chracters

blocks|key|3324138|text|仅字母数字TextBox+WPF+C#，|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3324139|对不起，我的英语..但是对于WPF的这个代码，c#，我只允许字母数字|3324140|private+void+txtTraslado_TextChanged(object+sender,+KeyEventArgs+e)
{
++if+(((e.Key+<+Key.NumPad0)%7C%7C(e.Key+>+Key.NumPad9))&&((e.Key+<+Key.A)%7C%7C(e.Key+>+Key.Z)))
++{
++++e.Handled+=+true;
++}
}|code-block|syntax|javascript|3324141|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

only alphanumeric TextBox WPF C#,

sorry for my english.. but with this code for WPF, c#, I only permit alphanumeric

<pre><code>private void txtTraslado_TextChanged(object sender, KeyEventArgs e)
{
 if (((e.Key &lt; Key.NumPad0)||(e.Key &gt; Key.NumPad9))&amp;&amp;((e.Key &lt; Key.A)||(e.Key &gt; Key.Z)))
 {
 e.Handled = true;
 }
}
</code></pre>

blocks|key|3111277|text|使用Asp.NET+AJAX控件工具包|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3111278|<%25@+Register+Assembly="AjaxControlToolkit"+Namespace="AjaxControlToolkit"+TagPrefix="asp"+%25>|code-block|syntax|javascript|3111279|并使用FilteredTextBoxExtender|3111280|<asp:TextBox+ID="txt_gpf_no"+runat="server"+CssClass="textbox"+
++++++++++++++++++++++++++++++++++++++++++++++++MaxLength="10"></asp:TextBox>
<asp:FilteredTextBoxExtender+ID="FilteredTextBoxExtender_gpf_no"+runat="server"+Enabled="True"
++++++++++++++++++++++++++++++++++++++++++++++++TargetControlID="txt_gpf_no"+FilterType="UppercaseLetters,LowercaseLetters,Custom"+ValidChars="1234567890+">
</asp:FilteredTextBoxExtender>|3111281|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Use Asp.NET AJAX Control Toolkit

<pre><code>&lt;%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %&gt;
</code></pre>

And Use FilteredTextBoxExtender 

<pre><code>&lt;asp:TextBox ID="txt_gpf_no" runat="server" CssClass="textbox" 
 MaxLength="10"&gt;&lt;/asp:TextBox&gt;
&lt;asp:FilteredTextBoxExtender ID="FilteredTextBoxExtender_gpf_no" runat="server" Enabled="True"
 TargetControlID="txt_gpf_no" FilterType="UppercaseLetters,LowercaseLetters,Custom" ValidChars="1234567890 "&gt;
&lt;/asp:FilteredTextBoxExtender&gt;
</code></pre>

blocks|key|340738|text|在my.Net+Framework4.5+C#应用程序中|type|unstyled|depth|inlineStyleRanges|entityRanges|data|340739|++++private+void+txtRF_Register_Val_KeyDown(object+sender,+KeyEventArgs+e)
++++{
++++++++//only+enable+alphanumeric
++++++++if+(!(((e.KeyCode+<+Keys.NumPad0)+%7C%7C+(e.KeyCode+>+Keys.NumPad9))+&&+((e.KeyCode+<+Keys.A)+%7C%7C+(e.KeyCode+>+Keys.E))))
++++++++{
++++++++++++e.SuppressKeyPress+=+false;
++++++++}
++++++++else
++++++++{
++++++++++++e.SuppressKeyPress+=+true;
++++++++}
++++}|code-block|syntax|javascript|340740|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

in my.Net Framework 4.5 C# application

<pre><code> private void txtRF_Register_Val_KeyDown(object sender, KeyEventArgs e)
 {
 //only enable alphanumeric
 if (!(((e.KeyCode &lt; Keys.NumPad0) || (e.KeyCode &gt; Keys.NumPad9)) &amp;&amp; ((e.KeyCode &lt; Keys.A) || (e.KeyCode &gt; Keys.E))))
 {
 e.SuppressKeyPress = false;
 }
 else
 {
 e.SuppressKeyPress = true;
 }
 }
</code></pre>

I have a textbox that should disallow entering any special characters.

The user can enter : 

<ol>
<li>A-Z </li>
<li>a-z </li>
<li>0-9 </li>
<li>Space</li>
</ol>

How can I make the <code>KeyDown</code> event to do this?

Allow only alphanumeric in textbox

我有一个文本框，不允许输入任何特殊字符。用户可以输入：A-Z a-z 0-9 Space怎样才能让KeyDown事件做到这一点呢？

问文本框中仅允许字母数字
EN

回答 13

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问文本框中仅允许字母数字EN

回答 13

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问文本框中仅允许字母数字
EN