c# WPF DataGridTextColumn自定义属性
本文关键字：自定义属性 DataGridTextColumn WPF | 更新日期: 2023-09-27 18:17:40
我试图将数据绑定到WPF中的某种自定义依赖项属性或附加属性。我用了下面的问题和回答-如何创建自定义属性的WPF DataGridTextColumn作为参考框架，但我需要绑定到WPF中的"标签"。我们可以叫它什么都行，为了简单起见，我叫它标签因为我在其他代码部分的复选框和文本框上使用它。我的班级如下:
public class TagTextColumns : DependencyObject
{
public static readonly DependencyProperty TagProperty = DependencyProperty.RegisterAttached(
"Tag",
typeof(object),
typeof(DataGridColumn),
new FrameworkPropertyMetadata(null));
public static object GetTag(DependencyObject dependencyObject)
{
return dependencyObject.GetValue(TagProperty);
}
public static void SetTag(DependencyObject dependencyObject, object value)
{
dependencyObject.SetValue(TagProperty, value);
}
}
我想在WPF中设置我的DataGridTextColumn，类似于以下内容:
<DataGridTextColumn Binding="{Binding Customer}" Header="Customer" local:TagTextColumns.Tag="{Binding tkey}"/>
，其中tkey是数据库中的引用。我这样做是为了计算每行最后一列的小计。现在，我用一个DataGridTemplateColumn，里面有一个TextBox，所以我可以用tkey来Tag我也在TechNet上读过这些东西，但似乎没有什么指向我到底想在这里做什么。我甚至不确定这是否可能，但看起来是可能的。
这是我用来尝试调用标签上的CellEditEnding发射的代码
private void resultsDg_CellEditEnding(object sender, DataGridCellEditEndingEventArgs e)
{
MessageBox.Show(TagTextColumns.GetTag(sender as DataGridTextColumn).ToString());
}
关于当前问题的更多细节:我正在尝试对数据库中的四个字段进行动态计算，以便在用户进行更改时计算最后一列的小计。我试图使用Linq到SQL为此，但使用System.Data.SqlClient和System.Data要快得多。也许有人能告诉我更好的方法。计算代码如下:
private void CalculateAscessorials(string tkey)
{
decimal SplitTerm = Properties.Settings.Default.SplitTerminal;
decimal SplitDrop = Properties.Settings.Default.SplitDrop;
decimal SiteSplit = Properties.Settings.Default.OnSiteSplit;
decimal Trainer = Properties.Settings.Default.TrainerLoad;
decimal WaitTime = Properties.Settings.Default.TerminalWait;
decimal PumpOut = Properties.Settings.Default.PumpOut;
DataRow[] row = resultDetail.Select("tkey = " + tkey);
decimal payRate;
decimal tempLineItem;
Decimal.TryParse(row[0]["PayForLine"].ToString(), out tempLineItem);
Decimal.TryParse(row[0]["PayRate"].ToString(), out payRate);
if (payRate == 0 && tempLineItem > 0) //this change affts if the rate is 0, that is no rate defined, the rate entered becomes the pay rate for that line only for calculations
row[0]["PayRate"] = tempLineItem;
if (!Convert.ToBoolean(row[0]["SplitDrop"]))
{
Decimal.TryParse(row[0]["PayRate"].ToString(), out payRate);
}
else if (Convert.ToBoolean(row[0]["SplitDrop"]))
{
payRate = SplitDrop;
}
//decimal linePay;
// Decimal.TryParse(row[0]["PayForLine"].ToString(), out linePay);
int terms;
Int32.TryParse(row[0]["SplitLoad"].ToString(), out terms);
decimal waits;
Decimal.TryParse(row[0]["WaitTime"].ToString(), out waits);
int pumps;
Int32.TryParse(row[0]["PumpOut"].ToString(), out pumps);
int sites;
Int32.TryParse(row[0]["SiteSplit"].ToString(), out sites);
int trainings;
Int32.TryParse(row[0]["Trainer"].ToString(), out trainings);
row[0]["PayForLine"] =
(SplitTerm * terms)
+ (waits * WaitTime)
+ (pumps * PumpOut)
+ (sites * SiteSplit)
+ (trainings * Trainer)
+ payRate;
}
您可以使用MVVM模式来计算ViewModel中的小计。这里有一个例子可以引导你找到正确的方向。在MainView的构造函数中，我创建了2个课程并申请学生。课程有一个属性TotalWeight，用于计算所有学生的总权重。如果一个学生的权重发生了变化，或者一个学生被添加/删除到课程中，我们必须更新UI上的值。这是由于INotifyPropertyChanged和ObservableCollection。
如果你使用LinqToSQL或更好的EntityFramework，你可以从商店。然后可以将它作为实际模型注入ViewModel构造函数。也许您甚至想为此目的引入MainViewModel。为了简单起见，我跳过了这个。但是您可能想了解一下依赖注入。
XAML: <DataGrid ItemsSource="{Binding}">
<DataGrid.RowDetailsTemplate>
<DataTemplate>
<DataGrid ItemsSource="{Binding Students}"></DataGrid>
</DataTemplate>
</DataGrid.RowDetailsTemplate>
</DataGrid>
背后的代码:
public class CourseViewModel : ViewModelBase
{
#region Fields
private string _name;
private ObservableCollection<StudentViewModel> _students;
#endregion Fields
#region Constructors
public CourseViewModel()
{
_students = new ObservableCollection<StudentViewModel>();
_students.CollectionChanged += _students_CollectionChanged;
}
#endregion Constructors
#region Properties
public string Name
{
get
{
return _name;
}
set
{
_name = value;
OnPropertyChanged();
}
}
public ObservableCollection<StudentViewModel> Students
{
get
{
return _students;
}
}
public double TotalWeight
{
get
{
return Students.Sum(x => x.Weight);
}
}
#endregion Properties
#region Methods
private void _students_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
// add/remove property changed handlers to students
if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
{
foreach (StudentViewModel student in e.NewItems)
{
student.PropertyChanged += Student_PropertyChanged;
}
}
if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Remove)
{
foreach (StudentViewModel student in e.OldItems)
{
student.PropertyChanged -= Student_PropertyChanged;
}
}
//students were added or removed to the course -> inform "listeners" that TotalWeight has changed
OnPropertyChanged(nameof(TotalWeight));
}
private void Student_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
//the weight of a student has changed -> inform "listeners" that TotalWeight has changed
if (e.PropertyName == nameof(StudentViewModel.Weight))
{
OnPropertyChanged(nameof(TotalWeight));
}
}
#endregion Methods
}
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
#region Constructors
public MainWindow()
{
InitializeComponent();
var course1 = new CourseViewModel() { Name = "Course1" };
course1.Students.Add(new StudentViewModel() { Weight = 100, Name = "Mark" });
course1.Students.Add(new StudentViewModel() { Weight = 120, Name = "Olaf" });
course1.Students.Add(new StudentViewModel() { Weight = 111, Name = "Hans" });
var course2 = new CourseViewModel() { Name = "Course2" };
course2.Students.Add(new StudentViewModel() { Weight = 100, Name = "Mark" });
course2.Students.Add(new StudentViewModel() { Weight = 90, Name = "Renate" });
course2.Students.Add(new StudentViewModel() { Weight = 78, Name = "Judy" });
DataContext = new List<CourseViewModel>()
{
course1,
course2
};
}
#endregion Constructors
}
public class StudentViewModel : ViewModelBase
{
#region Fields
private string _name;
private double _weight;
#endregion Fields
#region Properties
public string Name
{
get
{
return _name;
}
set
{
_name = value;
OnPropertyChanged();
}
}
public double Weight
{
get
{
return _weight;
}
set
{
_weight = value;
OnPropertyChanged();
}
}
#endregion Properties
}