Framework?Element.?Find?Name 根據名字查找控件
WPF Framework?Element.?Find?Name 根據名字查找控件
運行環境:Window7 64bit,NetFramework4.7,C# 7.0, 編者:烏龍哈裏 2017-10-04
參考:
- Framework?Element.?Find?Name Method
- Framework?Element.?Register?Name Method
章節:
正文:
最近寫個小玩意,本來是想用 TabControl 標明標簽,然後 TabItem 做容器裏面放些控件,但是我 TabItem裏面的控件完全一樣,用 TabItem 來做容器似乎太笨重了,於是想用個 StackPanel 來放標簽,其他控件用個 Grid 來包裹就成了。測試的時候發現 FindName()
Xaml 界面程序
<Window x:Class="學習FindName.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Title="MainWindow" Height="300" Width="300">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="6*"/>
<RowDefinition Height="1*"/>
<RowDefinition Height="32"/>
</Grid.RowDefinitions>
<StackPanel Name="stackpanel" Orientation="Horizontal" Grid.Row="1"/>
<Grid Grid.Row="2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*"/>
<ColumnDefinition Width="1*"/>
</Grid.ColumnDefinitions>
<Button Name="btnAdd" Content="添加" Margin="3" Grid.Column="0" Click="btnAdd_Click" />
<Button Name="btnDrop" Content="刪除" Margin="3" Grid.Column="1" Click="btnDrop_Click" />
</Grid>
</Grid>
</Window>
C# 後臺程序:
using System.Windows;
using System.Windows.Controls;
namespace 學習FindName
{
/// <summary>
/// MainWindow.xaml 的交互邏輯
/// </summary>
public partial class MainWindow : Window
{
private int RadioButtonNum = 0;
public MainWindow()
{
InitializeComponent();
}
//---添加 radiobutton
private void btnAdd_Click(object sender, RoutedEventArgs e)
{
RadioButtonNum++;
string s = "rbn" + RadioButtonNum.ToString();
RadioButton rbn = new RadioButton{ Name = s, Content = s,Margin=new Thickness(3)};
rbn.Click += RadioButton_Click;
stackpanel.Children.Add(rbn);
}
//---刪除 radiobutton
private void btnDrop_Click(object sender, RoutedEventArgs e)
{
string s = "rbn" + RadioButtonNum.ToString();
RadioButton rbn = stackpanel.FindName(s) as RadioButton;
stackpanel.Children.Remove(rbn);
}
private void RadioButton_Click(object sender, RoutedEventArgs e)
{
//(sender as RadioButton).IsChecked = true;
string s = (sender as RadioButton).Name;
RadioButtonNum = int.Parse(s[s.Length - 1].ToString());
lstShow.Items.Add(s);
}
}
}
運行效果如下:
但是刪除的時候,發現 FindName() 返回的值為 null,沒有找到控件。找了半天資料,才發現不在前臺 Xaml 裏面定義的控件名字,要用 ?Register?Name() 方式來註冊一下名字,後面的 FindName() 才能找到。
更改程序如下:
//---添加 radiobutton
private void btnAdd_Click(object sender, RoutedEventArgs e)
{
RadioButtonNum++;
string s = "rbn" + RadioButtonNum.ToString();
RadioButton rbn = new RadioButton{ Name = s, Content = s,Margin=new Thickness(3)};
rbn.Click += RadioButton_Click;
stackpanel.Children.Add(rbn);
//註冊一下名字,沒有這句後面的 FindName() 將找不到控件
stackpanel.RegisterName(s, rbn);
}
//---刪除 radiobutton
private void btnDrop_Click(object sender, RoutedEventArgs e)
{
string s = "rbn" + RadioButtonNum.ToString();
RadioButton rbn = stackpanel.FindName(s) as RadioButton;
rbn.Click -= RadioButton_Click;//事件如果不註銷,容易引起內存泄漏
stackpanel.Children.Remove(rbn);
}
private void RadioButton_Click(object sender, RoutedEventArgs e)
{
//(sender as RadioButton).IsChecked = true;
string s = (sender as RadioButton).Name;
RadioButtonNum = int.Parse(s[s.Length - 1].ToString());
lstShow.Items.Add(s);
}
運行效果如下:
Framework?Element.?Find?Name 根據名字查找控件