如何访问datagrid模板列文本框文本WPF C#

Question

我需要从后面的代码访问DataGrid 的模板列中的文本，但我不知道如何。我需要将文本更改为在SelectionChanged 事件中传递给它的任何字符串。有人可以告诉我如何实现这一目标吗？我发现了一个类似的问题here 但它没有答案。

Answer 1

要在DataGrid 模板列中查找控件，您应该使用FindChild()：

    public static T FindChild<T>(DependencyObject parent, string childName) where T : DependencyObject
    {
        if (parent == null)
        {
            return null;
        }

        T foundChild = null;

        int childrenCount = VisualTreeHelper.GetChildrenCount(parent);

        for (int i = 0; i < childrenCount; i++)
        {
            var child = VisualTreeHelper.GetChild(parent, i);
            T childType = child as T;

            if (childType == null)
            {
                foundChild = FindChild<T>(child, childName);

                if (foundChild != null) break;
            }
            else
                if (!string.IsNullOrEmpty(childName))
                {
                    var frameworkElement = child as FrameworkElement;

                    if (frameworkElement != null && frameworkElement.Name == childName)
                    {
                        foundChild = (T)child;
                        break;
                    }
                    else
                    {
                        foundChild = FindChild<T>(child, childName);

                        if (foundChild != null)
                        {
                            break;
                        }
                    }
                }
                else
                {
                    foundChild = (T)child;
                    break;
                }
        }

        return foundChild;
    }

例如，我在 MyDataGrid 中有这个模板列：

<DataGridTemplateColumn Width="1.5*" IsReadOnly="False">
    <DataGridTemplateColumn.Header>
        <TextBlock Text="Sample" ToolTip="{Binding Path=Text, RelativeSource={RelativeSource Self}}" FontSize="14" />
     </DataGridTemplateColumn.Header>

     <DataGridTemplateColumn.CellTemplate>
         <DataTemplate>
             <TextBlock x:Name="MyTextBlock" Text="Hello!" />
         </DataTemplate>
    </DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>

从代码中访问，你可以：

TextBlock MyTextBlock = FindChild<TextBlock>(MyDataGrid, "MyTextBlock");

MessageBox.Show(MyTextBlock.Text);

注意：只有在控件将完全加载时才使用FindChild，否则找不到它并给出null。在这种情况下，我将此代码放在事件 ContentRendered (Window) 中，它表示窗口的所有内容都已成功加载（即使事件 MyDataGrid_Loaded 也无法访问 MyTextBlock，因为它尚未加载):

    private void Window_ContentRendered(object sender, EventArgs e)
    {
        TextBlock MyTextBlock = FindChild<TextBlock>(MyDataGrid, "MyTextBlock");

        MessageBox.Show(MyTextBlock.Text);
    }

EDIT1：

要访问选定行的控件，将事件 SelectionChanged 添加到 DataGrid 中起作用，这将给出选定行：

    private void MyDataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        try
        {
            var row_list = GetDataGridRows(MyDataGrid);

            foreach (DataGridRow single_row in row_list)
            {
                if (single_row.IsSelected == true)
                {
                    TextBlock MyTextBlock = FindChild<TextBlock>(single_row, "MyTextBlock");

                    MessageBox.Show(MyTextBlock.Text);
                }
            }
        }

        catch 
        {
            throw new Exception("Can't get access to DataGridRow");
        }
    }

GetDataGridRows() 的列表：

    public IEnumerable<DataGridRow> GetDataGridRows(DataGrid grid)
    {
        var itemsSource = grid.ItemsSource as IEnumerable;

        if (null == itemsSource)
        {
            yield return null; 
        }

        foreach (var item in itemsSource)
        {
            var row = grid.ItemContainerGenerator.ContainerFromItem(item) as DataGridRow;

            if (null != row)
            {
                yield return row; 
            }
        }
    }

EDIT2：

为了获得 ALL 我重写了函数 FindChild() 的项目：

    public static void FindChildGroup<T>(DependencyObject parent, string childName, ref List<T> list) where T : DependencyObject
    {
        // Checks should be made, but preferably one time before calling.
        // And here it is assumed that the programmer has taken into
        // account all of these conditions and checks are not needed.
        //if ((parent == null) || (childName == null) || (<Type T is not inheritable from FrameworkElement>))
        //{
        //    return;
        //}

        int childrenCount = VisualTreeHelper.GetChildrenCount(parent);

        for (int i = 0; i < childrenCount; i++)
        {
            // Get the child
            var child = VisualTreeHelper.GetChild(parent, i);

            // Compare on conformity the type
            T child_Test = child as T;

            // Not compare - go next
            if (child_Test == null)
            {
                // Go the deep
                FindChildGroup<T>(child, childName, ref list);
            }
            else
            {
                // If match, then check the name of the item
                FrameworkElement child_Element = child_Test as FrameworkElement;

                if (child_Element.Name == childName)
                {
                    // Found
                    list.Add(child_Test);
                }

                // We are looking for further, perhaps there are
                // children with the same name
                FindChildGroup<T>(child, childName, ref list);
            }
        }

        return;
    }

调用这个新函数：

   private void Window_ContentRendered(object sender, EventArgs e)
   {
        // Create the List
        List<TextBlock> list = new List<TextBlock>();

        // Find all elements
        FindChildGroup<TextBlock>(MyDataGrid, "MyTextBlock", ref list);
        string text = "";

        // Print
        foreach (TextBlock elem in list)
        {
            text += elem.Text + "\n";
        }

        MessageBox.Show(text, "Text in TextBlock");
   }

一般来说，这种做法并不是最好的……要获取项目（例如 all 或 selected），您可以直接联系存储数据的列表（例如 ObservableCollection）。此外，它是有用的事件，例如 PropertyChanged。