将单个控件绑定到视图模型属性
将单个控件绑定到视图模型属性
提问于 2018-06-02 08:51:55
我正在尝试绑定TextBlock控件的文本，如下所示：
<TextBlock DataContext="ProgressViewModel" Text="{Binding FileName}" HorizontalAlignment="Center"/>"ProgressViewModel“是我的项目中存在的一个类，它公开了FileName属性：
private string _fileName;
public string FileName
{
get { return _fileName; }
set { this.MutateVerbose(ref _fileName, value, RaisePropertyChanged()); }
}我知道FileName正在被正确更新，因为我可以在调试器中查看它的值。但是，我不能让XAML绑定工作。我试图避免像一些文章建议的那样在Window.Resources中设置主绑定，因为我在这个项目中有多个视图模型。
全视图模型：
using MaterialDesignThemes.Wpf;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Threading.Tasks;
namespace MaterialDesignTest
{
public class ProgressViewModel : INotifyPropertyChanged
{
System.Windows.Forms.Timer progressTimer;
private double _saveProgressButton;
public double SaveProgressButton
{
get { return _saveProgressButton; }
set { this.MutateVerbose(ref _saveProgressButton, value, RaisePropertyChanged()); }
}
private string _fileName;
public string FileName
{
get { return _fileName; }
set { this.MutateVerbose(ref _fileName, value, RaisePropertyChanged()); }
}
private bool _isSaveComplete;
public bool IsSaveComplete
{
get { return _isSaveComplete; }
private set { this.MutateVerbose(ref _isSaveComplete, value, RaisePropertyChanged()); }
}
private bool _isSaving;
public bool IsSaving
{
get { return _isSaving; }
private set { this.MutateVerbose(ref _isSaving, value, RaisePropertyChanged()); }
}
int progress = 0;
int cycles = 0;
public ProgressViewModel()
{
}
public void KickOffProgressTimer()
{
progressTimer = new System.Windows.Forms.Timer();
progressTimer.Tick += new EventHandler(progressTimerTick);
progressTimer.Interval = 40;
progressTimer.Start();
}
private async void progressTimerTick(object sender, EventArgs e)
{
FileName = SelectRandomString();
if (progress < 100 && cycles < 2)
{
if (progress == 99)
{
cycles++;
progress = 0;
}
IsSaveComplete = false;
IsSaving = true;
progress++;
SaveProgressButton = progress;
}
else
{
IsSaveComplete = true;
IsSaving = false;
progressTimer.Enabled = false;
SaveProgressButton = 0;
await NonBlockingDelay(1750);
DialogHost.CloseDialogCommand.Execute(null, null);
}
}
async Task NonBlockingDelay(int value)
{
await Task.Delay(value);
}
public event PropertyChangedEventHandler PropertyChanged;
private Action<PropertyChangedEventArgs> RaisePropertyChanged()
{
return args => PropertyChanged?.Invoke(this, args);
}
static string SelectRandomString()
{
var random = new Random();
var questions = new List<string>{
@"C:\Files\Filename1",
@"C:\Filename2",
@"C:\Filename3",
@"C:\Filename4",
@"C:\Temp\Files\Filename5",
@"C:\Filename6",
@"C:\Demo\LongFolderName\Filename7",
@"C:\Filename8",
@"C:\Filename9",
};
int index = random.Next(questions.Count);
return(questions[index]);
}
}
}回答 1
Stack Overflow用户
发布于 2018-06-02 09:16:22
它不起作用，因为您当前绑定到字符串值"ProgressViewModel"；相反，您应该绑定到一个实例到一个ProgressViewModel类型的对象。尝试：
<TextBlock Text="{Binding FileName}" HorizontalAlignment="Center">
<TextBlock.DataContext>
<ns:ProgressViewModel />
</TextBlock.DataContext>
</TextBlock>在这里，我假设您在根标记中将包含ProgressViewModel的名称空间定义为ns。我还假设ProgressViewModel有一个公共的无参数构造函数。
下面是如何定义ns的。如果ProgressViewModel是在命名空间WpfApp1中定义的，那么ns应该写成这样：xmlns:ns="clr-namespace:WpfApp1"
namespace WpfApp1
{
public class ProgressViewModel
{
//...
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/50652580
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