将复选框绑定到具有Y N的字段 [英] bind checkbox to a field having Y N

问题描述

亲爱的所有人，

我在datacontext中有一个字段

nvarchar（1）

这个字段的值是''Y ''或''N''



我想将此字段绑定到wpf中的复选框



我已经使用事件完成了这项任务，但是我需要在Binding上实现这一点以实现标准编码风格



你能帮我绑定一个字符字段到一个复选框。



我知道boolean可以轻松限制但是字符字段呢。

''''用于检查

''N''未经检查。



希望我是有意义。



期待向您提供帮助。



关心

Dear All,
I have a field in datacontext as
nvarchar(1)
the values for this field are ''Y'' or ''N''

I want to bind this field to a checkbox in wpf

I have accomplished this task using events but I need to make this on Binding to acheive standard coding style

Can You please help me binding a character field to a checkbox.

I know boolean can be easily bounded but what about character field.
''Y'' for checked
''N'' For unchecked.

Hope I am making sense.

Looking forward to know from you for the help.

Regards

推荐答案

创建自定义 CheckBox 类，重载已检查属性。



VB.NET示例：

自定义类定义

Create custom CheckBox class with overloaded Checked property.

Example for VB.NET:
Custom class definition

Public Class MyCheckBox
    Inherits CheckBox

    Public Overloads Property Checked() As String
        Get
            Return BooleanToString(MyBase.Checked)
        End Get
        Set(ByVal value As String)
            MyBase.Checked = StringToBoolean(value)
        End Set
    End Property

    Private Function BooleanToString(ByVal b As Boolean) As String
        Return IIf(b, "Y", "N")
    End Function

    Private Function StringToBoolean(ByVal s As String) As Boolean
        Return IIf("Y", True, False)
    End Function


End Class

用法

Usage

    Dim mch As MyCheckBox = New MyCheckBox
    With mch
        .Location = New Point(8, 8)
        .Parent = Me 'this (form)
        .Text = "Check it"
        'add custom event handler
        AddHandler mch.CheckedChanged, AddressOf mcb_CheckedChanged
    End With


Private Sub mcb_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles mcb.CheckedChanged
    Dim oc As MyCheckBox = sender
    Me.Text = oc.Checked.ToString
End Sub

我希望上面的代码也适用于WPF。

I hope that above code can works for WPF too.

您可以使用转换器来完成此操作。就像BoolToVisibilityConverter一样，您可以创建YesNoToBoolConverter。这就是我要怎么做的：



这里是转换器：

Hi,

You can do this by using a converter. Just like a BoolToVisibilityConverter, you can create a YesNoToBoolConverter. Here''s how I would do it:

Here''s the converter:

public class YesNoToBooleanConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            if (value.ToString() == "Y")
                return true;
            else
                return false;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            if (value is bool)
            {
                if ((bool)value == true)
                    return "Y";
                else
                    return "N";
            }
            return null;
        }
    }

这里是VM：

And here''s the VM:

public class MainVM: ViewModelBase
 {
     string isChecked;
     public string IsChecked
     {
         get
         {
             return isChecked;
         }
         set
         {
             isChecked = value;
             base.RaisePropertyChanged("IsChecked");
         }
     }
 }

这里的观点是：

And here''s the view:

<window x:class="WpfApplication9.MainWindow" xmlns:x="#unknown">
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:WpfApplication9"
        Title="MainWindow" Height="350" Width="525">
    <stackpanel>
        <stackpanel.resources>
            <local:yesnotobooleanconverter x:key="YesNoConverter" xmlns:local="#unknown" />
        </stackpanel.resources>
        <checkbox ischecked="{Binding IsChecked, Converter={StaticResource YesNoConverter}}" />
    </stackpanel>
</window>

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        this.DataContext = new MainVM() { IsChecked = "N" } ;

    }
}

基本上，转换器会截取实际值绑定到您的属性并返回对该属性或视图友好的内容。



这是一个关于价值转换器的好教程：

http://wpftutorial.net/ValueConverters.html



希望这会有所帮助：）

Basically, the converter intercepts the actual value that was bound to your attribute and return something that is friendly to that attribute or to the view.

Here''s a good tutorial about value converter:
http://wpftutorial.net/ValueConverters.html

Hope this helps :)

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