Question

在我的课堂上，我为ListBoxItem编写了双击事件。单击listBox的条目时，它应仅返回该特定条目。但在我的情况下，虽然我点击了单个条目，但所有条目都被返回并且＆＃34; InvalidCastException＆＃34; occures。那么，我应该如何改变以获得单一条目。

这是双击事件代码：

private void ListBoxItem_DoubleClick(object sender, RoutedEventArgs e)
    {
        //Submit clicked Entry
        Harvest_TimeSheetEntry entryToPost = (Harvest_TimeSheetEntry)sender;

            if (!entryToPost.isSynced)
            {
                //Check if something is selected in selectedProjectItem For that item
             if (entryToPost.ProjectNameBinding == "Select Project")
                    MessageBox.Show("Please Select a Project for the Entry");
                else
                    Globals._globalController.harvestManager.postHarvestEntry(entryToPost);
            }
            else
            {
                //Already synced.. Make a noise or something
                MessageBox.Show("Already Synced;TODO Play a Sound Instead");
            }
    }

In xml:

<ListBox x:Name="listBox1" ItemsSource="{Binding}"  Margin="0,131,0,59" ItemTemplateSelector="{StaticResource templateSelector}" ListBoxItem.MouseDoubleClick="ListBoxItem_DoubleClick"/>

Answer 1

ListBox隐式将其项目包装到ListBoxItem中。尝试将sender转换为ListBoxItem，然后获取其Content属性

Answer 2

尝试使用运算符而不是直接转换，并在进一步处理之前包括空值检查

Answer 3

最后，它有效。

private void listBox1_MouseDoubleClick(object sender, MouseButtonEventArgs e)
    {
        //Submit clicked Entry
        try
        {
            ListBoxItem item = (ListBoxItem)sender;
            Harvest_TimeSheetEntry entryToPost = (Harvest_TimeSheetEntry)item.Content;

            if (!entryToPost.isSynced)
            {
                //Check if something is selected in selectedProjectItem For that item
                if (entryToPost.ProjectNameBinding == "Select Project")
                    MessageBox.Show("Please Select a Project for the Entry");
                else
                    Globals._globalController.harvestManager.postHarvestEntry(entryToPost);
            }
            else
            {
                //Already synced.. Make a noise or something
                MessageBox.Show("Already Synced;TODO Play a Sound Instead");
            }
        }
        catch (Exception)
        { }
     }

类型＆＃39; System.InvalidCastException＆＃39;的第一次机会异常发生了

3 个答案: