我试图从后面的代码中创建一个按钮,该按钮具有与此相同的属性:
<Button Content="Find Student" Tag="FindStudent" HorizontalAlignment="Right" x:Name="btnFindStudent" Click="btnGeneral_Click" />
后面的代码:
Button btnFindStudent = new Button();
btnFindStudent.Click += this.btnGeneral_Click;
btnFindStudent.Name = Convert.ToString("btnFindStudent");
btnFindStudent.Tag = Convert.ToString("FindStudent");
btnFindStudent.Content = Convert.ToString("View");
btnFindStudent.HorizontalAlignment = HorizontalAlignment.Right;
btnFindStudent.Height = 20;
btnFindStudent.Width = 36;
问题是当我单击按钮时出现错误
Value cannot be null.
Parameter name: Children of 'System.Windows.Controls.UIElementCollection' cannot be null. Object derived from UIElement expected.
而且我不太确定缺少什么,这是完整的代码:
public partial class FindStudent : UserControl
{
private Dictionary<string, UserControl> _userControls = new Dictionary<string, UserControl>();
public Dictionary<string, UserControl> GetUserControls()
{
return _userControls;
}
private static readonly Random rand = new Random();
public FindStudent()
{
InitializeComponent();
List<string> userControlKeys = new List<string>();
userControlKeys.Add("FindStudent");
Type type = this.GetType();
Assembly assembly = type.Assembly;
foreach (string userControlKey in userControlKeys)
{
string userControlFullName = String.Format("{0}.AppPages.{1}", type.Namespace, userControlKey);
UserControl userControl = (UserControl)assembly.CreateInstance(userControlFullName);
_userControls.Add(userControlKey, userControl);
}
for (int i = 1; i <= 10; i++)
{
Button btnFindStudent = new Button();
btnFindStudent.Click += this.btnGeneral_Click;
btnFindStudent.Name = Convert.ToString("btnFindStudent");
btnFindStudent.Tag = Convert.ToString("FindStudent");
btnFindStudent.Content = Convert.ToString("View {0}", i);
btnFindStudent.HorizontalAlignment = HorizontalAlignment.Right;
btnFindStudent.Height = 20;
btnFindStudent.Width = 36;
StackPanel stackPanel = new StackPanel();
stackPanel.Children.Add(btnFindStudent);
MainArea.Children.Add(stackPanel);
}
}
private void btnGeneral_Click(object sender, RoutedEventArgs e)
{
PanelMainContent.Children.Clear();
Button button = (Button)e.OriginalSource;
Type type = this.GetType();
Assembly assembly = type.Assembly;
PanelMainContent.Children.Add(_userControls[button.Tag.ToString()]);
// error on above line.
}
}
xml:
<UserControl x:Class="WpfApplication4.AppPages.FindStudent"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<DockPanel HorizontalAlignment="Stretch" >
<ScrollViewer VerticalScrollBarVisibility="Hidden">
<DockPanel x:Name="PanelMainWrapper" Margin="10,20,0,0">
<DockPanel x:Name="PanelMainContent" HorizontalAlignment="Stretch" VerticalAlignment="Top" Margin="0,30,0,0">
<ScrollViewer VerticalScrollBarVisibility="Hidden">
<WrapPanel x:Name="MainArea" VerticalAlignment="Bottom" HorizontalAlignment="Left">
</WrapPanel>
</ScrollViewer>
</DockPanel>
</DockPanel>
</ScrollViewer>
</DockPanel>
</UserControl>
它应该只是重新加载我当前使用的页面,我可以在以后设置 appPage,但它不想玩球。这在我的主窗口中有效,只是不在我的控件上,但我没有从后面的代码中设置按钮,我使用了我在主窗口中首先提到的 xaml。这告诉我我在单击按钮时遗漏了一些东西(我认为设置正确),标签设置正确但我不确定名称是否会像我的 xaml 代码一样是 x:Name。