WPF中的值绑定转换

2016-12-25 19:59:50来源:CSDN作者:lishuangquan1987人点击

在写程序中经常遇到这样的情况:本示例代码下载地址
点一个按钮,另外一个按钮或者几个被禁用掉,点另外的按钮,被禁用的按钮又恢复正常,平常的处理方法是在按钮点击事件中直接对其他按钮的IsEnable属性赋值来处理。但有时候复杂的情况导致我们常常担心这样的写法过于复杂,就几个按钮和一些控件的状态,我们能不能只管写逻辑代码,不去管这么多控件的ENABLE和DISABNLE呢?使用WPF中的绑定值转换可以达到这样的效果,举例说明:
这里写图片描述
如图中的三个按钮
点击修改:修改按钮:disable,取消按钮:enable,保存按钮:enable
点击取消:修改按钮:enable,取消按钮:disable,保存按钮:disable
点击保存:修改按钮:enable,取消按钮:disable,保存按钮:disable
利用WPF中的值绑定转换:转换部分的代码如下:

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Windows.Data;namespace WPF_BindingTest{   public class OperationTypeConverter:IValueConverter    {        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)        {            bool result = false;            if (parameter.ToString().Equals("Save"))//是save按钮            {                switch (value.ToString())                {                    case "Mod": result = true; break;                    case "None": result = false; break;                    default: result = false;                        break;                }            }            else if (parameter.ToString().Equals("Cancel"))//取消按钮            {                switch (value.ToString())                {                    case "Mod": result = true; break;                    case "None": result = false; break;                    default: result = false;                        break;                }            }            else//修改按钮            {                switch (value.ToString())                {                    case "Mod": result = false; break;                    case "None": result = true; break;                    default: result = false;                        break;                }            }            return result;        }        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)        {            throw new NotImplementedException();        }    }}

界面部分XAML代码如下:

<Window x:Class="WPF_BindingTest.MainWindow"        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"        xmlns:local="clr-namespace:WPF_BindingTest"        Title="MainWindow" Height="350" Width="525">    <Window.Resources>        <local:OperationTypeConverter x:Key="OpConverter"></local:OperationTypeConverter>    </Window.Resources>    <Grid>        <Button Content="修改" Command="{Binding ModCommand}" IsEnabled="{Binding CurrentStatus, Converter={StaticResource OpConverter}, ConverterParameter=Mod}" Name="btnMod" HorizontalAlignment="Left" Margin="69,208,0,0" VerticalAlignment="Top" Width="75"/>        <Button Content="取消" Command="{Binding CancelCommand}" IsEnabled="{Binding CurrentStatus, Converter={StaticResource OpConverter}, ConverterParameter=Cancel}" Name="btnCancel" HorizontalAlignment="Left" Margin="176,208,0,0" VerticalAlignment="Top" Width="75"/>        <Button Content="保存" Command="{Binding SaveCommand}" IsEnabled="{Binding CurrentStatus, Converter={StaticResource OpConverter}, ConverterParameter=Save}" Name="btnSave" HorizontalAlignment="Left" Margin="286,208,0,0" VerticalAlignment="Top" Width="75"/>    </Grid></Window>

ViewModel代码:

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.ComponentModel;using System.Windows.Input;namespace WPF_BindingTest{   public class MainWindowVM:INotifyPropertyChanged    {        public event PropertyChangedEventHandler PropertyChanged;        private void OnPropertyChanged(string name)        {            if (this.PropertyChanged != null)            {                this.PropertyChanged(this, new PropertyChangedEventArgs(name));            }        }        public MainWindowVM()        {            ModCommand = new CommonCommand(Modify);            CancelCommand = new CommonCommand(Cancel);            SaveCommand = new CommonCommand(Save);        }        #region 属性        private OperationStatus currentStatus = OperationStatus.None;        public OperationStatus CurrentStatus        {            get { return this.currentStatus; }            set { this.currentStatus = value; OnPropertyChanged("CurrentStatus"); }        }        private ICommand modCommand;        public ICommand ModCommand        {            get { return this.modCommand; }            set { this.modCommand = value; OnPropertyChanged("ModCommand"); }        }        private ICommand cancelCommand;        public ICommand CancelCommand        {            get { return this.cancelCommand; }            set { this.cancelCommand = value; OnPropertyChanged("CancelCommand"); }        }        private ICommand saveCommand;        public ICommand SaveCommand        {            get { return this.saveCommand; }            set { this.saveCommand = value; OnPropertyChanged("SaveCommand"); }        }        #endregion        #region 方法        private void Modify(object para)        {            CurrentStatus = OperationStatus.Mod;        }        private void Cancel(object para)        {            CurrentStatus = OperationStatus.None;        }        private void Save(object para)        {            CurrentStatus = OperationStatus.None;        }        #endregion    }   public enum OperationStatus   {       None,       Mod,        }}

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