WPF转换器无法正常工作

Question

朋友我第一次使用转换器。我想在Bool和String之间进行转换，以实现Button＆＃39; Help＆＃39;的可见性目的。 HelpVisibility的Getter-Setter正在运行，但我不确定为什么按钮的可见性不起作用。以下是我的代码。请帮忙。

VehicalForm.xaml

<Window x:Class="Seris.VehicleForm"
            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
            Title="MainWindow" Height="500" Width="650"
            xmlns:l="clr-namespace:Seris.Converters">
<Window.Resources>
    <l:Bool2String x:Key="converter" />
</Window.Resources>
<Control>

    <Control.Template>

        <ControlTemplate>

            <WrapPanel Orientation="Vertical" Margin="10 " >

                <Label Content="Vehical No" HorizontalAlignment="Left"/>
                <TextBox Name="VehicalNo_Text" Height="23" Width="80" TextWrapping="Wrap" Text="{Binding VehicalNo, UpdateSourceTrigger=PropertyChanged}"  HorizontalAlignment="Left" />

                <Label Content="Model" HorizontalAlignment="Left"/>
                <TextBox Name="Model_Text" Height="23" Width="80" TextWrapping="Wrap" Text="{Binding Model, UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left" />

                <Label Content="Manufacturing Date" HorizontalAlignment="Left"/>
                <DatePicker Name="ManufacturingDate_DateTime" SelectedDate="{Binding ManufacturingDate, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" Width="136"/>

                <Label Content="IU No" HorizontalAlignment="Left"/>
                <TextBox Height="23" Width="80" Name="IUNO_Text" TextWrapping="Wrap" Text="{Binding IUNo, UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left"/>

                <Label Content="Personnel" HorizontalAlignment="Left"/>
                <ComboBox Name="Personnel_Combo" SelectedValue="{Binding PersonnelNameSelected, UpdateSourceTrigger=PropertyChanged}" ItemsSource="{Binding PersonnelName, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" HorizontalAlignment="Left" Width="126"/>

                <Separator Height="20" RenderTransformOrigin="0.5,0.5" Width="16"/>

                <Button Name="Save_Button" Command="{Binding SaveButton_Command}" Content="Save" Width="66"/>
                <Button Name="Replace_Button" CommandParameter="replace" IsEnabled="{Binding isEnableReplaceButton, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" Command="{Binding ReplaceButton_Command}" Content="Replace" Width="66"/>
                <Button Name="Remove_Button" CommandParameter="replace" IsEnabled="{Binding isEnableReplaceButton, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" Command="{Binding RemoveButton_Command}" Content="Remove" Width="66"/>


                <Label x:Name="Error_Label" Content="{Binding ErrorMessage, UpdateSourceTrigger=PropertyChanged}" Foreground="Red" HorizontalAlignment="Left" Height="41" Width="137"/>

                <ListView Name ="Grid" Height="294" Width="371" >
                    <DataGrid Name="DG" ItemsSource="{Binding ListItems, UpdateSourceTrigger=PropertyChanged}" SelectedItem="{Binding SelectedRow, Mode=TwoWay}" GridLinesVisibility="None" IsReadOnly="True" AutoGenerateColumns="False" BorderThickness="0">
                        <DataGrid.Columns>
                            <DataGridTextColumn Header="Vehical No" Binding="{Binding VehicalNo}"/>
                            <DataGridTextColumn Header="Model" Binding="{Binding Model}" />
                            <DataGridTextColumn Header="ManufacturingDate" Binding="{Binding ManufacturingDate}" />
                            <DataGridTextColumn Header="IUNo" Binding="{Binding IUNo}" />
                            <DataGridTextColumn Header="Personnel" Binding="{Binding PersonnelNameSelected}" />
                        </DataGrid.Columns>
                    </DataGrid>
                </ListView>

                <TextBlock Name="Notification" Text="{Binding EditText, UpdateSourceTrigger=PropertyChanged}"/>

                <ProgressBar Name="Progressbar" Minimum="0" Maximum="100" Value="{Binding Progress, UpdateSourceTrigger=PropertyChanged}" Height="11"/>
                <TextBlock Text="{Binding ElementName=Progressbar, Path=Value, StringFormat={}{0:0}%}" HorizontalAlignment="Center" VerticalAlignment="Center" />

                <Button Name="Help" Visibility="{Binding HelpVisibility, Converter={StaticResource converter}, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" CommandParameter="help" Height="50" Width="50" Click="Help_Click" HorizontalAlignment="Right">
                    <Image Height="45" Width="45" Source="../Images/help.jpg" HorizontalAlignment="Left"/>
                </Button>

            </WrapPanel>

        </ControlTemplate>

    </Control.Template>

</Control>

</Window>

Bool2String.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Data;

namespace Seris.Converters
{
class Bool2String : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is bool)
            return bool.TrueString;
        return null;
    }
    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {

        if (value is string)
        {
            if (value == "true")
                return true;
            else if (value == "false")
                return false;
        }
        return null;
    }
}
}

VehicalMainViewModel.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Seris.Models;
using System.Collections.ObjectModel;
using System.Windows.Input;
using Seris.Commands;
using Seris.ViewModels;
using System.Windows;
using System.Windows.Controls;
using System.Threading;
using System.ComponentModel;
using Seris.Views;

namespace Seris.ViewModels
{
public class VehicleMainViewModel : ObservableObject
{


    #region Getters-Setters

    // Static Variables

    private static bool _IsEnableReplaceButton;
    public static bool IsEnableReplaceButton
    {
        get { return _IsEnableReplaceButton; }
        set { _IsEnableReplaceButton = value; }
    }

    // Non-Static Variables

    public ObservableCollection<VehicleModel> _listItems;

    public ObservableCollection<VehicleModel> ListItems
    {
        get { return _listItems; }
        set
        {
            if (value == null || (!value.Equals(_listItems)))
            {
                _listItems = value;
            }
        }
    }


    private int _Progress;

    public int Progress
    {
        get { return _Progress; }
        set { _Progress = value; OnPropertyChanged("Progress"); }
    }

    private string _ErroMesage;

    public string ErrorMessage
    {
        get { return _ErroMesage; }
        set 
        { 
            _ErroMesage = value; OnPropertyChanged("ErrorMessage");
            if (ErrorMessage.Trim() == "" || ErrorMessage == null)
                HelpVisibility = false;
            else
                HelpVisibility = true;
        }
    }

    private bool _HelpVisibility;
    public bool HelpVisibility
    {
        get { return _HelpVisibility; }
        set { _HelpVisibility = value; OnPropertyChanged("HelpVisibility"); }
    }


    private Guid? _UniqueNo;

    public Guid? UniqueNo 
    {
        get { return _UniqueNo; }
        set
        {
            if (value == null || (!value.Equals(_UniqueNo)))
            {
                _UniqueNo = value;
                OnPropertyChanged("VehicalNo");

            }
        }
    }

    private string _VehicalNo;

    public string VehicalNo 
    {
        get { return _VehicalNo; }
        set
        {
            if (value == null || (!value.Equals(_VehicalNo)))
            {
                _VehicalNo = value;
                EditText = _VehicalNo;
                OnPropertyChanged("VehicalNo");

            }
        }
    }
    private string _Model;

    public string Model
    {
        get { return _Model; }
        set
        {
            if (value == null || (!value.Equals(_Model)))
            {
                _Model = value;
                EditText = _Model;
                OnPropertyChanged("Model");
            }
        }
    }
    private DateTime? _ManufacturingDate;

    public DateTime? ManufacturingDate
    {
        get { return _ManufacturingDate; }
        set
        {
            if (value == null || (!value.Equals(_ManufacturingDate)))
            {
                _ManufacturingDate = value;
                EditText = _ManufacturingDate.ToString();
                OnPropertyChanged("ManufacturingDate");
            }
        }
    }
    private string _IUNo;

    public string IUNo
    {
        get { return _IUNo; }
        set
        {
            if (value == null || (!value.Equals(_IUNo)))
            {
                _IUNo = value;
                EditText = _IUNo;
                OnPropertyChanged("IUNo");
            }
        }
    }
    private ObservableCollection<string> _PersonnelName;

    public ObservableCollection<string> PersonnelName
    {
        get { return _PersonnelName; }
        set
        {
            if (value != _PersonnelName)
            {
                _PersonnelName = value;
                EditText = _VehicalNo;
                OnPropertyChanged("PersonnelName");
            }
        }
    }

    private string _PersonnelNameSelected;

    public string PersonnelNameSelected
    {
        get { return _PersonnelNameSelected; }
        set
        {
            if (value != _PersonnelNameSelected)
            {
                _PersonnelNameSelected = value;
                EditText = _PersonnelNameSelected;
                OnPropertyChanged("PersonnelNameSelected");
            }
        }
    }

    private string _EditText;

    public string EditText
    {
        get { return _EditText; }
        set
        {
            if (value != _EditText)
            {
                _EditText = value;
                OnPropertyChanged("EditText");
            }
        }
    }

    private VehicleModel _SelectedRow;
    public VehicleModel SelectedRow
    {
        get { return _SelectedRow; }
        set
        {
            if (value != _SelectedRow)
            {
                _SelectedRow = value;
                OnPropertyChanged("SelectedRow");

                if (SelectedRow != null)
                {
                    UniqueNo = _SelectedRow.UniqueNo;
                    VehicalNo = _SelectedRow.VehicalNo;
                    Model = _SelectedRow.Model;
                    ManufacturingDate = _SelectedRow.ManufacturingDate;
                    IUNo = _SelectedRow.IUNo;
                    PersonnelNameSelected = _SelectedRow.PersonnelNameSelected;

                    _IsEnableReplaceButton = true;
                }

            }
        }
    } 
    #endregion

    #region Command Objects
    private ICommand _saveButton_Command;

    public ICommand SaveButton_Command
    {
        get { return _saveButton_Command; }
        set { _saveButton_Command = value; }
    }

    private ICommand _ReplaceButton_Command;

    public ICommand ReplaceButton_Command
    {
        get { return _ReplaceButton_Command; }
        set { _ReplaceButton_Command = value; }
    }

    private ICommand _RemoveButton_Command;

    public ICommand RemoveButton_Command
    {
        get { return _RemoveButton_Command; }
        set { _RemoveButton_Command = value; }
    }
    #endregion

    #region Methods

    //Static Methods



    #region Constructors

    public VehicleMainViewModel()
    {
        // Initialization
        VehicleModel vm = new VehicleModel();
        ListItems = new ObservableCollection<VehicleModel>();
        PersonnelName = ListOfPersonnelViewModel.PersonNameList_Updating;
        //PersonnelName = new ObservableCollection<string>() { "ABC", "DEF", "GHI" };

        // Setting Flags
        ErrorMessage = "";
        IsEnableReplaceButton = false;
        //



        // Commands Initialization
        SaveButton_Command = new RelayCommand(new Action<object>(SaveToList));
        ReplaceButton_Command = new RelayCommand(new Action<object>(ReplaceToList));
        RemoveButton_Command = new RelayCommand(new Action<object>(RemoveList));

    } 

    #endregion


}
}

Answer 1

在转换器中，您应该返回Visibilty.Visible或Visibility.Collapsed，而不是true或false或字符串。

Answer 2

可见性属性接受值为＆＃34;隐藏＆＃34;，＆＃34;折叠＆＃34;或＆＃34;可见＆＃34;。您需要将这些值设置为Visibility属性。

您可以参考以下链接获取BoolToVisibilityconverter的代码 WPF Converter Property

如果你发现它有用，请不要忘记回答。