控件之DataGrid----实现自动添加新行和数据交换

Silverlight的很多控件相对于VS的其他程序来说，还很不成熟，Datagrid就是其中一个，可能个人比较愚笨，经过好几天才把一些问题搞清楚了。

 

先描述一下自己这个测试程序的功能。

 

1，Datagrid上显示10条信息，在最后面另外显示一条空信息，当其中的内容被改变以后，这条信息存入数据源中，Datagrid的最后重新添加一行空信息

2，通过上下键实现数据的交换，比如当前选择的index是5，按了向下的箭头之后，5和6交换，光标跟随5到6的位置上。

3，添加，插入，删除数据操作

 

实现中出现的问题：

1，需要确定初始index，开始决定使用Datagrid的SelectionChanged事件来获取

 

private void dg_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
           
            m_CurrentIndex = dg.SelectedIndex ;
           
        }

 

然后在KeyUp事件中交换

 private void dg_KeyUp(object sender, KeyEventArgs e) { //MessageBox.Show(dg.SelectedIndex.ToString()); if (e.Key == Key.Up) { if (m_CurrentIndex != dg.SelectedIndex) { Data tem = source[m_CurrentIndex - 1]; source[m_CurrentIndex - 1] = source[m_CurrentIndex]; source[m_CurrentIndex] = tem; //source.Insert(dg.SelectedIndex, source[m_CurrentIndex]); //source.RemoveAt(m_CurrentIndex + 1); dg.ItemsSource = null; dg.ItemsSource = UpDateTempSource(source); //m_CurrentIndex = dg.SelectedIndex; m_CurrentIndex = m_CurrentIndex - 1; dg.SelectedIndex = m_CurrentIndex; } } if (e.Key == Key.Down) { if (m_CurrentIndex != dg.SelectedIndex) { if (dg.SelectedIndex < source.Count - 1) { Data tem = source[m_CurrentIndex + 1]; source[m_CurrentIndex + 1] = source[m_CurrentIndex]; source[m_CurrentIndex] = tem; //source.Insert(dg.SelectedIndex, source[m_CurrentIndex]); //source.RemoveAt(m_CurrentIndex + 1); dg.ItemsSource = null; dg.ItemsSource = UpDateTempSource(source); //m_CurrentIndex = dg.SelectedIndex; m_CurrentIndex = m_CurrentIndex + 1; dg.SelectedIndex = m_CurrentIndex; } } }

问题出现了，每次按下上下键，SelectedIndex都会改变，因此在KeyUp中的这个判断if (m_CurrentIndex != dg.SelectedIndex)就失去了作用，不会响应。

然后考虑过使用MouseLeftButtonDown事件，但是这个事件居然只在表头才有作用...幸好随后又尝试了MouseLeftButtonUp事件，才顺利的实现了获取初始index的功能。

private void dg_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {
            m_CurrentIndex = dg.SelectedIndex;
        }

 

另外，键盘上的方向键也不响应DataGrid的KeyDown事件，而KenUp事件则是响应的，不知道为什么...

 

2，数据交换后更新DataGrid，这个是跟优快云的达人们学习的

dg.ItemsSource = null;
dg.ItemsSource = tempSource;

先将数据源设置为null，然后重新设置数据源，OK，搞定

 

3，最后的空行不能交换，为实现这个功能，定义了两个数据列表

            int itemsCount = 10; for (int i = 0; i < itemsCount; i++) { source.Add(new Data() { FirstName = "First", LastName = "Last", Age = i.ToString(), }); } tempSource = UpDateTempSource(source); dg.ItemsSource = tempSource;

其中的source用来用来执行数据交换，tempSource作为dg的数据源，最后添加了空行，确保最后一行不被交换，用

if (dg.SelectedIndex < source.Count - 1)进行判断。

 

 

完整代码： 

 

 
MainPage.cs

public class Data { public string FirstName { get; set; } public string LastName { get; set; } public string Age { get; set; } } public partial class MainPage : UserControl { List<Data> source = new List<Data>(); List<Data> tempSource = new List<Data>(); DataGrid dataGrid = new DataGrid(); private int m_CurrentIndex = 0; public MainPage() { InitializeComponent(); int itemsCount = 10; for (int i = 0; i < itemsCount; i++) { source.Add(new Data() { FirstName = "First", LastName = "Last", Age = i.ToString(), }); } dg.ItemsSource = UpDateTempSource(source); dg.FrozenColumnCount = 1; dg.CellEditEnded+=new EventHandler<DataGridCellEditEndedEventArgs>(dg_CellEditEnded); dg.MouseLeftButtonUp+=new MouseButtonEventHandler(dg_MouseLeftButtonUp); dg.KeyUp+=new KeyEventHandler(dg_KeyUp); } private List<Data> UpDateTempSource(List<Data> source) { tempSource.Clear(); for (int i = 0; i < source.Count; i++) { tempSource.Add(source[i]); } tempSource.Add(new Data() { FirstName = "*", LastName = "", Age = "", }); return tempSource; } private void dg_MouseLeftButtonUp(object sender, MouseButtonEventArgs e) { m_CurrentIndex = dg.SelectedIndex; } private void dg_KeyUp(object sender, KeyEventArgs e) { if (e.Key == Key.Up) { if (m_CurrentIndex != dg.SelectedIndex) { Data tem = source[m_CurrentIndex - 1]; source[m_CurrentIndex - 1] = source[m_CurrentIndex]; source[m_CurrentIndex] = tem; dg.ItemsSource = null; dg.ItemsSource = UpDateTempSource(source); m_CurrentIndex = m_CurrentIndex - 1; dg.SelectedIndex = m_CurrentIndex; } } if (e.Key == Key.Down) { if (m_CurrentIndex != dg.SelectedIndex) { if (dg.SelectedIndex < source.Count - 1) { Data tem = source[m_CurrentIndex + 1]; source[m_CurrentIndex + 1] = source[m_CurrentIndex]; source[m_CurrentIndex] = tem; dg.ItemsSource = null; dg.ItemsSource = UpDateTempSource(source); m_CurrentIndex = m_CurrentIndex + 1; dg.SelectedIndex = m_CurrentIndex; } } } } private void dg_CellEditEnded(object sender, DataGridCellEditEndedEventArgs e) { if (dg.SelectedIndex == source.Count-1) { dg.ItemsSource = null; source.Add(new Data() { FirstName = "*", LastName = "", Age = "", }); dg.ItemsSource = UpDateTempSource(source); } } private void btnDelete_Click(object sender, RoutedEventArgs e) { if (dg.SelectedIndex < 0) { return; } else { source.RemoveAt(dg.SelectedIndex); dg.ItemsSource = null; dg.ItemsSource = UpDateTempSource(source); } } private void btnInsert_Click(object sender, RoutedEventArgs e) { if (dg.SelectedIndex < 0) { return; } else { source.Insert(dg.SelectedIndex, new Data() { FirstName = "F", LastName = "L", Age = (source.Count - 1).ToString() }); dg.ItemsSource = null; dg.ItemsSource = UpDateTempSource(source); } } }