如何使用MVVM模式在WPF datagrid中绑定CurrentCell

问题描述

我正在学习WPF MVVM模式。我被困在绑定CurrentCell 中的 datagrid 。基本上我需要当前单元格的行索引和列索引。

 < DataGrid AutoGenerateColumns =True
 SelectionUnit =Cell
 CanUserDeleteRows =True
 ItemsSource ={Binding Results}
 CurrentCell ={Binding CellInfo}
 Height =282
 Horizo​​ntalAlignment =Left
 Margin =12,88,0,0
 Name =dataGrid1
 VerticalAlignment =Top
宽度=558
 SelectionMode =Single> 
  

这是我的ViewModel

  private User procedureName = new User（）; 
 
 public DataGridCell CellInfo 
 {
 get {return procedureName.CellInfo; } 
 // set 
 // {
 // procedureName.CellInfo = value; 
 // OnPropertyChanged（CellInfo）; 
 //} 
} 
  

这是我的模型

  private DataGridCell cellInfo; 
 
 public DataGridCell CellInfo 
 {
 get {return cellInfo; } 
 // set 
 // {
 // cellInfo = value; 
 // OnPropertyChanged（CellInfo）; 
 //} 
} 
  

在我的ViewModel中 CellInfo 总是 null 。我不能从 datagrid 中的 currentcell 获取值。请让我知道一种在ViewModel中获取 CurrentCell 的方法。

  if（CellInfo！= null）
 {
 MessageBox.Show（Value is+ CellInfo.Column.DisplayIndex.ToString（））; 
} 
  

解决方案

周围我注意到了一个非常简单的解决方案来解决您的问题。

首先，有两个问题，而不是一个。您不能绑定类型为 DataGridCell 的 CellInfo ，则需要 DataGridCellInfo 因为xaml不能自己转换。

其次在你的xaml中，你需要添加 Mode = OneWayToSource 或 Mode = TwoWay 到您的 CellInfo 绑定。

这是一个与您的原始代码半关系的粗略示例

XAML

 < DataGrid AutoGenerateColumns =True
 SelectionUnit =Cell
 SelectionMode =Single
 Height =250Width =525
 ItemsSource ={Binding Results}
 CurrentCell ={Binding CellInfo，Mode = OneWayToSource}/> 
  

VM

  private DataGridCellInfo _cellInfo; 
 public DataGridCellInfo CellInfo 
 {
 get {return _cellInfo; } 
 set 
 {
 _cellInfo = value; 
 OnPropertyChanged（CellInfo）; 
 MessageBox.Show（string.Format（Column：{0}，
 _cellInfo.Column.DisplayIndex！= null？_cellInfo.Column.DisplayIndex.ToString（）：索引超出范围！ ））; 
} 
} 
  

只是一个小小的提示 - 如果你调试你的应用程序看看输出窗口，它实际上告诉你绑定是否有麻烦。

希望这有帮助！

K。

I'm learning WPF MVVM pattern. I'm stuck in Binding CurrentCell of datagrid. Basically I need the row index and column index of current cell.

<DataGrid AutoGenerateColumns="True"
          SelectionUnit="Cell"
          CanUserDeleteRows="True"
          ItemsSource="{Binding Results}"
          CurrentCell="{Binding CellInfo}"
          Height="282"
          HorizontalAlignment="Left"
          Margin="12,88,0,0"
          Name="dataGrid1"
          VerticalAlignment="Top"
          Width="558"
          SelectionMode="Single">

Here is my ViewModel

private User procedureName = new User();

public  DataGridCell   CellInfo
{
    get { return procedureName.CellInfo; }
    //set
    //{
    //    procedureName.CellInfo = value;
    //    OnPropertyChanged("CellInfo");
    //}
}

Here is my Model

private DataGridCell cellInfo;

public DataGridCell CellInfo
{
    get { return cellInfo; }
    //set
    //{
    //    cellInfo = value;
    //    OnPropertyChanged("CellInfo");
    //}
}

And in my ViewModel CellInfo is always null. I am not able to get the value from the currentcell in datagrid. Please let me know a way to getCurrentCell in the ViewModel.

if (CellInfo != null)
{
    MessageBox.Show("Value is" + CellInfo.Column.DisplayIndex.ToString());
}

解决方案

After having a quick poke-around I've noticed a very simple solution to your problem.

First of all there's two problems rather then one here. You cannot bind a CellInfo of a type DataGridCell, it needs to be DataGridCellInfo as xaml cannot convert it on its own.

Secondly in your xaml you will need to add Mode=OneWayToSource or Mode=TwoWay to your CellInfo binding.

Here is a rough example semi-related to your original code

XAML

<DataGrid AutoGenerateColumns="True"
          SelectionUnit="Cell"
          SelectionMode="Single"
          Height="250" Width="525"
          ItemsSource="{Binding Results}"
          CurrentCell="{Binding CellInfo, Mode=OneWayToSource}"/>

VM

private DataGridCellInfo _cellInfo;
public DataGridCellInfo CellInfo
{
    get { return _cellInfo; }
    set
    {
        _cellInfo = value;
        OnPropertyChanged("CellInfo");
        MessageBox.Show(string.Format("Column: {0}",
                        _cellInfo.Column.DisplayIndex != null ? _cellInfo.Column.DisplayIndex.ToString() : "Index out of range!"));
    }
}

Just a small tip - if you debug your app and look at the Output window it actually tells you if there is any troubles with your bindings.

Hope this helps!

K.

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