Wpf xaml当我点击编辑它时检查组合框值是否为空。如果value不为null，如何禁用组合框 [英] Wpf xaml when I click edit it checks if combobox value is null or not. How to disable combobox if value is not null

问题描述

  private  CarType _inspectMethod; 
 
  public  CarType InspectMethod 
 {
 
  get  
 {
  return  _inspectMethod; 
} 
  set  
 {
 
 _inspectMethod =  value ; 
 RaisePropertyChanged（）; 
 
  if （InspectMethod！=  null ）
 {
 InspectTypelist = InspectMethod.InspectType; 
} 
} 
 
< Label Grid.Row =   0 Grid.Column =   0 Content =   value： /> 
< ComboBox Width =   Auto Grid.Row =   4 Grid.Column =   1 SelectedValuePath =   Id 
 DisplayMemberPath = < span class =code-string> 名称 SelectedItem =   {Binding ElementName = LayoutRoot，
 Path = DataContext.InspectMethod} ItemsSource =   {Binding 
 ElementName = LayoutRoot，Path = DataContext.InspectMethodList} /> 

我尝试过：

  bool  _isEnable; 
  public   bool  IsEnable 
 
 {
  get  
 {
  return   this  ._ isEnable; 
} 
 
  set  
 {
  this  ._ isEnable =  value ; 
} 
} 
 
< ComboBox Width =   Auto  Grid.Row =   4 Grid.Column =   1 IsEnable =  绑定一些东西 SelectedValuePath =   Id 
 DisplayMemberPath =  名称 SelectedItem =   {Binding ElementName = LayoutRoot，
 Path = DataContext.InspectMethod} ItemsSource =   {绑定
 ElementName = LayoutRoot，Path = DataContext.InspectMethodList} /> 

解决方案

< blockquote>你是什么意思combobox va略。你的意思是enable-diable组合框有没有项目列表。如果是这种情况，您可以使用以下代码

  public   class  ComboBoxEnableConverter：IValueConverter 
 {
  public   object 转换（ object   value ，输入targetType，对象参数，CultureInfo文化）
 {
  bool  hasItem =（ bool ） value ; 
  if （hasItem）
  return  真; 
  return   false ; 
} 
  public   object  ConvertBack（ object   value ，输入targetType， object 参数，CultureInfo文化）
 { 
  throw   new  NotImplementedException（）; 
} 
} 
 

然后添加到资源并绑定到启用属性，如下所示< br $>

 <   UserControl .Resources  >  
 <   common：ComboBoxEnableConverter     x：Key   =  EnableConverter  /  >  
 <   / UserControl.Resources  >  
 
 <   ComboBox     x：名称  =  cmboBox    IsEnabled   =  {Binding ElementName = cmboBox，Path = HasItems，Converter = {StaticResource EnableConverter}}  /  >  

1.如果要将源值转换为目标，请定义转换器，例如，项目计数为布尔值（IsEnable on接受布尔值）

2.绑定IsEnable财产符合您的要求。在这个例子中，我想检查组合框是否在项目源中有一些项目。如果是，则Converter将返回true，否则为false

private CarType _inspectMethod;
    
    public CarType InspectMethod
    {
    
            get
            {
                return _inspectMethod;
            }
            set
            {
     
                _inspectMethod= value;
                RaisePropertyChanged();
                
             if(InspectMethod!= null)
                {                    
                    InspectTypelist = InspectMethod.InspectType;
                }
    }   

    <Label Grid.Row="0" Grid.Column="0" Content="value:" />
   <ComboBox Width="Auto" Grid.Row="4" Grid.Column="1" SelectedValuePath="Id" 
    DisplayMemberPath="Name" SelectedItem="{ Binding ElementName=LayoutRoot, 
    Path=DataContext.InspectMethod}" ItemsSource="{ Binding 
    ElementName=LayoutRoot, Path=DataContext.InspectMethodList}"/>

What I have tried:

bool _isEnable;
 public bool IsEnable

        {
            get
            {
                return this._isEnable;
            }

            set
            {
                this._isEnable = value;
            }
        }

 <ComboBox Width="Auto" Grid.Row="4" Grid.Column="1" IsEnable="Binding something here" SelectedValuePath="Id" 
    DisplayMemberPath="Name" SelectedItem="{ Binding ElementName=LayoutRoot, 
    Path=DataContext.InspectMethod}" ItemsSource="{ Binding 
    ElementName=LayoutRoot, Path=DataContext.InspectMethodList}"/>

解决方案

What do you mean by combobox value. do you mean enable-diable combo box has list of items or not. If this is the case, you can use following code

public class ComboBoxEnableConverter : IValueConverter
   {
       public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
       {
           bool hasItem = (bool)value;
           if (hasItem)
               return true;
           return false;
       }
       public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
       {
           throw new NotImplementedException();
       }
   }

Then Add to Resource and bind to Enable property as given below

<UserControl.Resources>
        <common:ComboBoxEnableConverter x:Key="EnableConverter"/>
</UserControl.Resources>

<ComboBox x:Name="cmboBox" IsEnabled="{Binding ElementName=cmboBox, Path=HasItems, Converter={StaticResource EnableConverter}}"/>

1. Define converter if you want to convert source value into target e.g items count to boolean (IsEnable on accepts boolean)
2. Bind IsEnable property to your requirement. In this example I want to check if combo box has some items in item source. if yes, Converter will return true, else false

这篇关于Wpf xaml当我点击编辑它时检查组合框值是否为空。如果value不为null，如何禁用组合框的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！