Question

我是wpf和xaml（一般来说是Windows开发）的新手，我的背景是asp.net，在那之前是经典的asp。我正在处理一个应用程序，需要在处理过程中禁用/灰显按钮，并在此处阅读帖子以执行以下操作，但它似乎不起作用。有人会帮助我解决我错过的问题吗？

<Window x:Class="SCGen.Application.LoadForecast.EngineExecution"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:igEditors="http://infragistics.com/Editors"        
    SizeToContent="WidthAndHeight"
    Title="Engine Execution"
    ResizeMode="NoResize"
    WindowStartupLocation="CenterOwner"
    Background="{StaticResource {x:Static SystemColors.ControlBrushKey}}">
<Window.Resources>
    <Style TargetType="{x:Type Button}" x:Key="myStyle" BasedOn="{StaticResource ButtonStyle}">
        <Setter Property="Command" Value="{Binding ExecuteEngine}" />
        <Setter Property="Content" Value="Execute Engine" />
        <Style.Triggers>
            <Trigger Property="Command" Value="{x:Null}">
                <Setter Property="IsEnabled" Value="False"/>
            </Trigger>
        </Style.Triggers>
    </Style>
</Window.Resources>    
<Border Padding="8">
    <StackPanel>
        <StackPanel MaxWidth="200" HorizontalAlignment="Left">
            <TextBlock Text="Select Forecast Engine" TextAlignment="Center" FontSize="13" />

            <igEditors:XamComboEditor ItemsSource="{Binding ForecastEngines}" SelectedItem="{Binding SelectedEngine}" Margin="0,5" />

            <Button Style="{StaticResource ResourceKey=myStyle}" />
        </StackPanel>

        <TextBlock Text="{Binding EngineStatus}" FontSize="15" FontStyle="Italic" Margin="0,14" Width="400" TextWrapping="Wrap" />
    </StackPanel>
</Border>

谢谢

我已将xaml更改为以下内容：

<Button Content="Execute Weather Import" Command="{Binding ExecuteWeather}" Style="{StaticResource ButtonStyle}" IsEnabled="{Binding IsEnabled}"/>

在ViewModel中，我有以下内容：

private bool _isEnabled = true;
    public bool IsEnabled
    { 
        get { return _isEnabled; }
        set { _isEnabled = value; }
    }

我在这里设置了_isEnabled：

private string LaunchWeatherImport(string strVendor)
    {
        _isEnabled = false;

        string uri = ConfigurationManager.AppSettings["ManualExecutionFacilitatorService"];
        ClientConnectionInfo connection = new ClientConnectionInfo(uri) { UseSecurity = true };
        connection.SetTimeouts();

        Logger.LogInfo("Calling Facilitator service to manually import " + strVendor + " weather data.");

        ((NetTcpBinding)connection.Binding).Security.Mode = System.ServiceModel.SecurityMode.None;

        using (var client = new FacilitatorManualExecutionClient(connection))
        {
            client.InnerChannel.OperationTimeout = TimeSpan.FromMinutes(int.Parse(ConfigurationManager.AppSettings["OperationTimeOutMinutes"]));

            try
            {
                _isEnabled = true;
                return "success";
                // uncomment this line before commit
                //return client.ExecuteWeather(strVendor);
            }
            #region catch
            catch (Exception ex)
            {
                Logger.LogError(ex.Message, ex);
                return ex.Message;
            }
            #endregion
        }
    }

我仍然无法正常工作。很抱歉不得不添加到此，但评论的回复字段不足以发布代码。

Answer 1

对于初学者，您在Command属性上设置了触发器，但您没有为该按钮设置该属性的绑定：

<Button Style="{StaticResource ResourceKey=myStyle}" />

应该是：

<Button Style="{StaticResource ResourceKey=myStyle}" Command="{Binding MyCommand}" />

[其中MyCommand是您绑定的实际命令的名称]

我不确定它是否会起作用，因为当Command属性为null时触发器设置为触发，但是如果绑定到命令属性，则遵循MVVM模式，那么命令属性不应为null所以触发器也不会触发。

更新：

您需要在您的类上实现具有该属性的INotifyPropertyChanged接口。

public class MyClass : System.ComponentModel.INotifyPropertyChanged

然后添加实现：

public event PropertyChangedEventHandler PropertyChanged;

private void NotifyPropertyChanged(String info)
{
    if (PropertyChanged != null)
    {
        PropertyChanged(this, new PropertyChangedEventArgs(info));
    }
}

然后将您的属性更改为：

private bool _isEnabled = true;
public bool IsEnabled
{ 
    get { return _isEnabled; }
    set 
    { 
       _isEnabled = value;
       NotifyPropertyChanged("IsEnabled");
    }
}

处理请求时禁用按钮

1 个答案: