我确信已经有人问过这个问题,但我对 MVVM 和 WPF 仍然很陌生,不太确定我应该搜索什么。
我有一个 View 模型,其中包含模型中的项目,以及一些附加的临时数据项,这些数据项将全部传递给 process.start()。我有一个文本框堆栈面板,希望允许用户输入“ModelName”,如果存在,ViewModel 将获取并设置与 ModelName 关联的“TemplateName”。
我对如何实现这个有点迷失。我是否需要创建一个完全独立的 ViewModel,然后从 ModelViewModel 中提取数据?我是否只需在 ModelName 的集合下编写一些代码,即可在其中验证、查询和设置 TemplateName?
型号:
public partial class Model
{
public string ModelName { get; set; }
public virtual Template Template { get; set; }
和 ViewModel,它采用模型和一些临时数据:
public class LauncherViewModel:ViewModelBase
{
public LauncherViewModel()
{
_ESTContext = new ESTContext();
Models = new ObservableCollection<Model>(_ESTContext.Models);
}
private ESTContext _ESTContext;
private string _modelname;
private string _serialno;
private string _sonumber;
private string _templatename;
private string _outputname;
private Model _selectedmodel;
public ObservableCollection<Model> Models { get; set; }
public string ModelName
{
get { return _modelname; }
set
{
if (!string.Equals(_modelname, value))
{
_modelname = value;
};
}
}
public string TemplateName { get { return _templatename; }}
public string SerialNo { get { return _serialno; } }
public string SONumber { get { return _sonumber; } }
public string OutputName { get { return _outputname; } }
public Model SelectedModel
{
get { return _selectedmodel; }
set
{
if (_selectedmodel != value)
{
_selectedmodel = value;
}
}
}
}
我的观点:
<DockPanel>
<StackPanel Margin="0,78,0,68" Width="233" DataContext="{Binding Models}">
<ComboBox IsEditable="True" Text="{Binding ModelName}" SelectedItem="{Binding SelectedModel}"/>
<TextBox Height="23" TextWrapping="Wrap" Text="{Binding SONumber}"/>
<TextBox Height="23" TextWrapping="Wrap" Text="{Binding SerialNumber}"/>
<Button Content="Button"/>
</StackPanel>
</DockPanel>
最佳答案
要更新您的 gui,您必须实现 INotifyPropertyChanged 并在所有绑定(bind)属性上调用它。
// basic base class for your models, you a
public class ModelBase : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
[NotifyPropertyChangedInvocator] // remove if you are not using R#
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}
// your model
public class Model : ModelBase
{
private string modelName;
private Template template;
public string ModelName
{
get { return modelName; }
set
{
if (value == modelName) return;
modelName = value;
OnPropertyChanged();
}
}
public virtual Template Template
{
get { return template; }
set
{
if (Equals(value, template)) return;
template = value;
OnPropertyChanged();
}
}
}
查看:
<DockPanel>
<StackPanel Margin="0,78,0,68" Width="233">
<ComboBox IsEditable="True" Text="{Binding ModelName, Mode='TwoWay'}" SelectedItem="{Binding SelectedModel}" ItemsSource="{Binding Models}"/>
<TextBox Height="23" TextWrapping="Wrap" Text="{Binding SONumber Mode='TwoWay'}"/>
<TextBox Height="23" TextWrapping="Wrap" Text="{Binding SerialNumber Mode='TwoWay'}"/>
<Button Content="Button"/>
</StackPanel>
请注意,Mode='TwoWay' 这会使 GUI 更改 View 模型中的值,而不仅仅是显示它们。因此,您需要对所有应该可编辑的内容进行设置,如上所述。 WPF 的默认行为是,当控件失去焦点时,它将更新绑定(bind)的属性,如果设置 UpdateSourceTrigger='PropertyChanged',则每次在文本框中输入字母时,属性都会更新。我会把这部分留给你,但你必须在你的虚拟机中完成它!至少属性 SONumber、SerialNumber 和 Models(如果引用发生更改)。
VM:我假设你在这里使用galasoft
public class LauncherViewModel : ViewModelBase
{
private ESTContext _ESTContext;
private string _templatename;
private string _modelname;
private string serialNumber;
private string _outputname;
private string modelName;
private ObservableCollection<Model> models;
private Model selectedModel;
private string soNumber;
public LauncherViewModel()
{
// dangerous ;)
_ESTContext = new ESTContext();
Models = new ObservableCollection<Model>(_ESTContext.Models);
}
public ObservableCollection<Model> Models
{
get { return models; }
set
{
if (Equals(value, models)) return;
models = value;
RaisePropertyChanged();
}
}
public string ModelName
{
get { return modelName; }
set
{
if (value == modelName) return;
modelName = value;
RaisePropertyChanged();
}
}
public string TemplateName { get { return _templatename; }}
public string SerialNumber // Note you spelled this wrong in your xaml. SONumber
{
get { return serialNumber; }
set
{
if (value == serialNumber) return;
serialNumber = value;
RaisePropertyChanged();
}
}
public string SONumber
{
get { return soNumber; }
set
{
if (value == soNumber) return;
soNumber = value;
RaisePropertyChanged();
}
}
public string OutputName { get { return _outputname; } }
public Model SelectedModel
{
get { return selectedModel; }
set
{
if (Equals(value, selectedModel)) return;
selectedModel = value;
RaisePropertyChanged();
}
}
}
如果您将 galasoft 或 sim 与 R# 一起使用,这是一件很酷的小事。
public class YourViewModelBase : ViewModelBase
{
[NotifyPropertyChangedInvocator] // alt + enter = convert auto property to prop
// with backing field and change notification :)
override protected void RaisePropertyChanged([CallerMemberName] string propertyName = null)
{
base.RaisePropertyChanged(propertyName);
}
// .. :)
}
干杯,
斯蒂安
关于c# - 用于获取/设置 View 模型的文本框输入,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/25389502/