[英]Validation in textbox in WPF
我目前正在开发一个WPF应用程序,我想要一个只能在其中包含数字条目的TextBox
。 我知道当我丢失焦点并阻止内容为数字时我可以验证它的内容,但在其他Windows窗体应用程序中,我们使用完全阻止除了数字之外的任何输入被写下来。 另外,我们使用这个代码放在一个单独的dll中,以便在很多地方引用它。
以下是2008年不使用WPF的代码:
Public Shared Sub BloquerInt(ByRef e As System.Windows.Forms.KeyPressEventArgs, ByRef oTxt As Windows.Forms.TextBox, ByVal intlongueur As Integer)
Dim intLongueurSelect As Integer = oTxt.SelectionLength
Dim intPosCurseur As Integer = oTxt.SelectionStart
Dim strValeurTxtBox As String = oTxt.Text.Substring(0, intPosCurseur) & oTxt.Text.Substring(intPosCurseur + intLongueurSelect, oTxt.Text.Length - intPosCurseur - intLongueurSelect)
If IsNumeric(e.KeyChar) OrElse _
Microsoft.VisualBasic.Asc(e.KeyChar) = System.Windows.Forms.Keys.Back Then
If Microsoft.VisualBasic.AscW(e.KeyChar) = System.Windows.Forms.Keys.Back Then
e.Handled = False
ElseIf strValeurTxtBox.Length < intlongueur Then
e.Handled = False
Else
e.Handled = True
End If
Else
e.Handled = True
End If
在WPF中有相同的方法吗? 我不介意这是一个风格,但我是WPF的新手,所以风格有点模糊他们能做什么或不能做什么。
您只能使用TextBox上的附加属性将输入限制为数字。 定义附加属性一次(即使在单独的dll中)并在任何TextBox上使用它。 这是附属物:
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
/// <summary>
/// Class that provides the TextBox attached property
/// </summary>
public static class TextBoxService
{
/// <summary>
/// TextBox Attached Dependency Property
/// </summary>
public static readonly DependencyProperty IsNumericOnlyProperty = DependencyProperty.RegisterAttached(
"IsNumericOnly",
typeof(bool),
typeof(TextBoxService),
new UIPropertyMetadata(false, OnIsNumericOnlyChanged));
/// <summary>
/// Gets the IsNumericOnly property. This dependency property indicates the text box only allows numeric or not.
/// </summary>
/// <param name="d"><see cref="DependencyObject"/> to get the property from</param>
/// <returns>The value of the StatusBarContent property</returns>
public static bool GetIsNumericOnly(DependencyObject d)
{
return (bool)d.GetValue(IsNumericOnlyProperty);
}
/// <summary>
/// Sets the IsNumericOnly property. This dependency property indicates the text box only allows numeric or not.
/// </summary>
/// <param name="d"><see cref="DependencyObject"/> to set the property on</param>
/// <param name="value">value of the property</param>
public static void SetIsNumericOnly(DependencyObject d, bool value)
{
d.SetValue(IsNumericOnlyProperty, value);
}
/// <summary>
/// Handles changes to the IsNumericOnly property.
/// </summary>
/// <param name="d"><see cref="DependencyObject"/> that fired the event</param>
/// <param name="e">A <see cref="DependencyPropertyChangedEventArgs"/> that contains the event data.</param>
private static void OnIsNumericOnlyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
bool isNumericOnly = (bool)e.NewValue;
TextBox textBox = (TextBox)d;
if (isNumericOnly)
{
textBox.PreviewTextInput += BlockNonDigitCharacters;
textBox.PreviewKeyDown += ReviewKeyDown;
}
else
{
textBox.PreviewTextInput -= BlockNonDigitCharacters;
textBox.PreviewKeyDown -= ReviewKeyDown;
}
}
/// <summary>
/// Disallows non-digit character.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">An <see cref="TextCompositionEventArgs"/> that contains the event data.</param>
private static void BlockNonDigitCharacters(object sender, TextCompositionEventArgs e)
{
foreach (char ch in e.Text)
{
if (!Char.IsDigit(ch))
{
e.Handled = true;
}
}
}
/// <summary>
/// Disallows a space key.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">An <see cref="KeyEventArgs"/> that contains the event data.</param>
private static void ReviewKeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Space)
{
// Disallow the space key, which doesn't raise a PreviewTextInput event.
e.Handled = true;
}
}
}
以下是如何使用它(将“controls”替换为您自己的命名空间):
<TextBox controls:TextBoxService.IsNumericOnly="True" />
您可以在绑定中进行验证
<TextBox>
<TextBox.Text>
<Binding Path="CategoriaSeleccionada.ColorFondo"
UpdateSourceTrigger="PropertyChanged">
<Binding.ValidationRules>
<utilities:RGBValidationRule />
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>
看看这个例子(我的程序),你把验证放在绑定里面就像这样。 使用UpdateSourceTrigger,您可以更改绑定时的更新(丢失焦点,每次更改...)
好吧,验证是一个类,我会举个例子:
class RGBValidationRule : ValidationRule
{
public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
{
// Here you make your validation using the value object.
// If you want to check if the object is only numbers you can
// Use some built-in method
string blah = value.ToString();
int num;
bool isNum = int.TryParse(blah, out num);
if (isNum) return new ValidationResult(true, null);
else return new ValidationResult(false, "It's no a number");
}
}
简而言之,在该方法中完成工作并返回一个新的ValidationResult。 第一个参数是bool,如果验证是好的,则为true,否则为false。 第二个参数只是一条信息消息。
我认为这是文本框验证的基础知识。
希望这有帮助。
编辑:对不起,我不知道VB.NET,但我认为C#代码非常简单。
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