CPF 入门教程 - 数据绑定和命令绑定（二）

CPF netcore跨平台UI框架

系列教程 1b1c

CPF 入门教程（一）

CPF 入门教程 - 数据绑定和命令绑定（二）

数据绑定和Wpf类似，支持双向绑定。数据绑定和命令绑定是UI和业务逻辑分离的基础。

首先，你需要定义个MainModel，为了可以有属性通知，这个类可以继承CpfObject或者自己实现INotifyPropertyChanged

public class MainModel : CpfObject
{
[PropertyMetadata("默认值")]
public string Test
{
get { return (string)GetValue(); }
set { SetValue(value); }
}
}

这里定义了一个Test属性，并且设置默认值为“默认值”

设计个测试界面，加个TextBlock和Button，同时TextBlock设置绑定，绑定定义在Bindings属性， {nameof(TextBlock.Text),nameof(MainModel.Test) } 表示TextBlock的Text绑定到DataContext的Test属性

public class Window4 : Window
{
protected override void InitializeComponent()
{
Title = "标题";
Width = 344.8f;
Height = 126.4f;
Background = null;
Children.Add(new WindowFrame(this, new Panel
{
Width = "100%",
Height = "100%",
Children =
{
//内容元素放这里
new Button
{
MarginLeft = 223.8f,
MarginTop = 25.7f,
Height = 28f,
Width = 67.4f,
Content = "Button",
},
new TextBlock
{
MarginLeft = 36.7f,
MarginTop = 31.6f,
Text = "TextBlock",
Bindings =
{
{nameof(TextBlock.Text),nameof(MainModel.Test) }
}
},
}
}));
LoadStyleFile("res://ConsoleApp1.Stylesheet1.css");
//加载样式文件，文件需要设置为内嵌资源

}
}

修改program，设置Window的DataContext和CommandContext

var model = new MainModel();
Application.Run(new Window4 { DataContext = model, CommandContext = model });

写好之后，运行看看效果。TextBlock那边显示MainModel那边定义的默认值

接下来定义命令，通过按钮点击修改Test值，同时自动更新到TextBlock

MainModel里增加个Click方法

class MainModel :
ad8
CpfObject
{
[PropertyMetadata("默认值")]
public string Test
{
get
{
return (string)GetValue();
}
set
{
SetValue(value);
}
}

public void Click()
{
Test += "test";
}
}

Button那边增加命令绑定，Commands里添加， {nameof(Button.Click),nameof(MainModel.Click) } 表示Button的Click事件绑定到CommandContext的Click方法

new Button
{
MarginLeft = 223.8f,
MarginTop = 25.7f,
Height = 28f,
Width = 67.4f,
Content = "Button",
Commands =
{
{nameof(Button.Click),nameof(MainModel.Click) }
}
},

运行效果，点击一次增加一次test。这就是最简单的模型视图分离的数据绑定

接下来绑定集合

设计界面，添加Button和ListBox

往MainModel里加上Items集合属性，构造函数里初始化集合，用 Collection 是为了有集合变化通知，也可以使用 ObservableCollection。 (string, string) 就是元组里简化的结构体类型定义，是一种偷懒简化数据定义的方式，不过这种方式的话，改item就不能更新到UI了，需要可以更新到UI的就需要自定义类型，继承CpfObject或者继承INotifyPropertyChanged的类型作为Item

public MainModel()
{
Items = new Collection<(string, string)>();
}

public Collection<(string,string)> Items
{
get
{
return (Collection<(string, string)>)GetValue();
}
set
{
SetValue(value);
}
}

MainModel里加个AddItem方法

public void AddItem()
{
Items.Add(("test" + Items.Count, Items.Count.ToString()));
}

最终代码

using CPF;
using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApp1
{
class MainModel : CpfObject
{
[Pr
ad0
opertyMetadata("默认值")]
public string Test
{
get
{
return (string)GetValue();
}
set
{
SetValue(value);
}
}

public void Click()
{
Test += "test";
}

public MainModel()
{
Items = new Collection<(string, string)>();
}

public Collection<(string, string)> Items
{
get
{
return (Collection<(string, string)>)GetValue();
}
set
{
SetValue(value);
}
}

public void AddItem()
{
Items.Add(("test" + Items.Count, Items.Count.ToString()));
}
}
}

using System;
using System.Collections.Generic;
1044

using System.Linq;
using System.Text;
using CPF;
using CPF.Drawing;
using CPF.Controls;
using CPF.Shapes;
using CPF.Styling;
using CPF.Animation;

namespace ConsoleApp1
{
public class Window4 : Window
{
protected override void InitializeComponent()
{
Title = "标题";
Width = 338.4f;
Height = 205.6f;
Background = null;
Children.Add(new WindowFrame(this, new Panel
{
Width = "100%",
Height = "100%",
Children =
{
//内容元素放这里
new Button
{
MarginLeft = 223.8f,
MarginTop = 25.7f,
Height = 28f,
Width = 67.4f,
Content = "Button",
Commands =
{
{
nameof(Button.Click),
nameof(MainModel.Click)
}
}
},
new TextBlock
{
MarginLeft = 36.7f,
MarginTop = 31.6f,
Text = "TextBlock",
Bindings =

15b0
{
{
nameof(TextBlock.Text),
nameof(MainModel.Test)
}
}
},
new Button
{
MarginLeft = 223.8f,
MarginTop = 91.6f,
Height = 28f,
Width = 67.4f,
Content = "添加Item",
Commands =
{
{nameof(Button.Click),nameof(MainModel.AddItem) }
}
},
new ListBox
{
SelectedValuePath = "Item2",//绑定Item里的Item1属性
DisplayMemberPath = "Item1",//绑定Item里的Item2属性
BorderStroke = "1,Solid",
BorderFill = "#DEDEDE",
MarginLeft = 36.7f,
MarginTop = 60.8f,
Height = 76.5f,
Width = 123.2f,
Bindings =
{
{nameof(ListBox.Items),nameof(MainModel.Items) }
}
},
}
}));
LoadStyleFile("res://ConsoleApp1.Stylesheet1.css");
//加载样式文件，文件需要设置为内嵌资源
}
}
}

最终运行效果，点击添加Item的按钮，ListBox里会增加Item

数据类型转换，Test属性值后面加1。 数据转换器用方法或者Lambda就行。

{
nameof(TextBlock.Text),
nameof(MainModel.Test),
null,
BindingMode.OneWay,
(string a)=>a+"1"
}

UI元素之间绑定，TextBox的Text绑定到Button的Content，其中TextBox设置PresenterFor=this,是为了标记TextBox的作用域在当前类，因为Name是可以重复的，元素嵌套如果有相同Name会无法判断元素是在哪里的，所以用PresenterFor加标记判断，而且这样可以通过FindPresenterByName方法来获取当前类里的标记元素来绑定

protected override void InitializeComponent()
{
Title = "标题";
Width = 338.4f;
Height = 205.6f
15a8
;
Background = null;
Children.Add(new WindowFrame(this, new Panel
{
Width = "100%",
Height = "100%",
Children =
{
//内容元素放这里
new Button
{
MarginLeft = 223.8f,
MarginTop = 25.7f,
Height = 28f,
Width = 67.4f,
Content = "Button",
Commands =
{
{
nameof(Button.Click),
nameof(MainModel.Click)
}
},
Bindings =
{
{
nameof(Button.Content),
nameof(TextBox.Text),
FindPresenterByName("textBox")
}
}
},
new TextBlock
{
MarginLeft = 36.7f,
MarginTop = 31.6f,
Text = "TextBlock",
Bindings =
{
{
nameof(TextBlock.Text),
nameof(MainModel.Test),
null,
BindingMode.OneWay,
(string a)=>a+"1"
}
}
},
new Button
{
MarginLeft = 223.8f,
MarginTop = 91.6f,
Height = 28f,
Width = 67.4f,
Content = "添加Item",
Commands =
{
{
nameof(Button.Click),
nameof(MainModel.AddItem)
}
}
},
new ListBox
{
SelectedValuePath = "Item2",
//绑定Item里的Item1属性
DisplayMemberPath = "Item1",
//绑定Item里的Item2属性
BorderStroke = "1,Solid",
BorderFill = "#DEDEDE",
MarginLeft = 36.7f,
MarginTop = 60.8f,
Height = 76.5f,
Width = 123.2f,
Bindings =
{
{
nameof(ListBox.Items),
nameof(MainModel.Items)
}
}
},
new TextBox
{

17a2
Name="textBox",
PresenterFor=this,
AcceptsReturn= false,
HScrollBarVisibility= ScrollBarVisibility.Hidden,
VScrollBarVisibility= ScrollBarVisibility.Hidden,
MarginLeft = 144.8f,
MarginTop = 28.1f,
Width = 74.5f
},
}
}));
LoadStyleFile("res://ConsoleApp1.Stylesheet1.css");
//加载样式文件，文件需要设置为内嵌资源
}

TextBox输入，会自动更新Button的文字

命令绑定除了事件之外，属性变化也可以绑定为命令，比如，鼠标移入和移出就调用

Commands =
{
{
nameof(Button.IsMouseOver),
nameof(MainModel.Click)
}
}

主要绑定就这些，如果要双向绑定，命令参数等等，看VS那边的智能提示