MVVM(Model-View-ViewModel):Model指的是后台传递的数据,View指的是所看到的页面。ViewModel是mvvm模式的核心，它是连接view和model的桥梁。它有两个方向：一是将模型转化成视图，即将后端传递的数据转化成所看到的页面。实现的方式是： 数据绑定。二是将视图转化成模型，即将所看到的页面转化成后端的数据
Wpf 使用MVVM模式的优点:
1.结构清晰明朗，上手成本低，一个新人也能快速的定位自己需要改动代码的位置。
2.耦合度低，更改WPF控件不影响数据结构，更改代码成本低。
3.可重用性高，比如一个处理逻辑放到ViewModel模块中，其他界面如果要用掉直接调用即可。
当然并不是所有的项目都去使用MVVM开发，一些简单的我们也可以按照正常的开发。
使用WPF MvvM模式
在先创建的项目中新建三个文件夹:
Views,Models,ViewModels文件夹:
Views文件夹中存放视图;
Models:文件夹中存放模式;
ViewModels文件夹中存放业务逻辑;
当做完这些操作时项目的文件目录是这样的:
下面这个示例是我的实现: 视图:(MainWindow.xaml)
视图代码:
<Window.Resources>
<Style TargetType="TextBlock">
<Setter Property="FontSize" Value="18"></Setter>
<Setter Property="HorizontalAlignment" Value="Center"></Setter>
<Setter Property="FontWeight" Value="Black"></Setter>
<Setter Property="Margin" Value="0 30"></Setter>
<Setter Property="Width" Value="350"></Setter>
</Style>
<Style TargetType="TextBox">
<Setter Property="Width" Value="150"></Setter>
<Setter Property="Height" Value="30"></Setter>
<Setter Property="Margin" Value="10 0 0 0"></Setter>
<Setter Property="HorizontalAlignment" Value="Center"></Setter>
<Setter Property="VerticalAlignment" Value="Center"></Setter>
<Setter Property="FontSize" Value="16"></Setter>
<Setter Property="Padding" Value="3"></Setter>
</Style>
<Style TargetType="Button">
<Setter Property="BorderThickness" Value="0"></Setter>
<Setter Property="Background" Value="Blue"></Setter>
<Setter Property="Width" Value="100"></Setter>
<Setter Property="HorizontalAlignment" Value="Center"></Setter>
<Setter Property="Height" Value="40"></Setter>
<Setter Property="FontSize" Value="16"></Setter>
<Setter Property="FontWeight" Value="Black"></Setter>
<Setter Property="Foreground" Value="#FFF"></Setter>
<Setter Property="Margin" Value="10 0 0 0"></Setter>
</Style>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="auto"></RowDefinition>
<RowDefinition> </RowDefinition>
</Grid.RowDefinitions>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Title}"></TextBlock>
<!--<TextBox Text="{Binding Mcontent}"></TextBox>-->
<!--Command是一个命令类型的属性
获取或设置按下此按钮时要调用的命令。
-->
<Button Content="点击" x:Name="Search" Command="{Binding SearchCommand}"></Button>
</StackPanel>
<DataGrid x:Name="Daone" Grid.Row="1" IsReadOnly="True" HorizontalAlignment="Stretch" AutoGenerateColumns="False"
CanUserResizeColumns="False" CanUserResizeRows="False" SelectionMode="Single"
AlternationCount="2" ItemsSource="{Binding StaffS}" RowHeaderWidth="0" CanUserAddRows="False" Background="White" >
<!--给整个表头添加颜色开始-->
<DataGrid.ColumnHeaderStyle>
<Style TargetType="DataGridColumnHeader">
<Setter Property="Background">
<Setter.Value>
<LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
<GradientStop Color="White" Offset="0"/>
<GradientStop Color="LightBlue" Offset="0.5"/>
<GradientStop Color="White" Offset="1"/>
</LinearGradientBrush>
</Setter.Value>
</Setter>
<Setter Property="Foreground" Value="Black"/>
<Setter Property="FontSize" Value="13" />
</Style>
</DataGrid.ColumnHeaderStyle>
<!--隔行变色-->
<DataGrid.RowStyle>
<Style TargetType="{x:Type DataGridRow}">
<Setter Property="FontSize" Value="12"></Setter>
<Style.Triggers>
<Trigger Property="ItemsControl.AlternationIndex" Value="0">
<Setter Property="Background" Value="#cbedfa"></Setter>
</Trigger>
<Trigger Property="ItemsControl.AlternationIndex" Value="1">
<Setter Property="Background" Value="#FFF"></Setter>
</Trigger>
</Style.Triggers>
</Style>
</DataGrid.RowStyle>
<DataGrid.Columns>
<DataGridTextColumn Header="Id" Width="*" Binding="{Binding Id}"></DataGridTextColumn>
<DataGridTextColumn Header="姓名" Width="*" Binding="{Binding Name}"></DataGridTextColumn>
<DataGridTextColumn Header="地址" Width="*" Binding="{Binding address}"></DataGridTextColumn>
<DataGridTextColumn Header="年龄" Width="*" Binding="{Binding age}"></DataGridTextColumn>
<DataGridTextColumn Header="性别" Width="*" Binding="{Binding gender}"></DataGridTextColumn>
<DataGridTextColumn Header="联系电话" Width="*" Binding="{Binding Contactnumber}"></DataGridTextColumn>
</DataGrid.Columns>
</DataGrid>
</Grid>
MainWindow.xaml.cs `
public MainWindow()
{
InitializeComponent();
//页面的数据绑定
this.DataContext =new MainViewModel();
//这里实现的是视图的关闭;
//WindowManager.Reister<MainWindow>("MainWindow");
//表格的数据绑定
//Daone.DataContext = new MainViewModel();
}
模型 Staff.cs
namespace WpfApp2.Models
{
public class Staff
{
public int Id { get; set; }
//名字
public string Name { get; set; }
//年龄
public string age { get; set; }
//性别
public Gender gender { get; set; }
//家庭地址
public string address { get; set; }
//联系电话
public string Contactnumber { get; set; }
}
public enum Gender
{
女 = 0,
男 = 1,
}
}
视图模型 MainViewModel.cs
public class MainViewModel:ViewModelUtil
{
//observableCollection 表示一个动态数据集，该集合在项目获取时提供通知
//添加、删除或刷新整个列表时。.
ObservableCollection<Staff> staffs=new ObservableCollection<Staff>();
public ObservableCollection<Staff> StaffS
{
//get 用于获取属性的值,
get { return staffs; }
//Set 用于设置字段的值;
set { StaffS = value;RaisPropertyChanged("StaffS"); }
}
public MainViewModel()
{
#region 数据源
Selectstaff();
#endregion
//#region Linq语句 的格式
//var linqList = list.Where(t => t < 10) //列表中值小于10
// .GroupBy(t => t) //分组
// .Where(t => t.Count() > 1) //分组后出现次数大于1
// .OrderByDescending(t => t.Count()) //按照出现次数倒序
// .Select(t => t.Key); //选择值
//#endregion
SearchCommand = new RelayCommand((arg) =>
{
//将窗口新增值哈希表;
WindowManager.Reister<AddStaff>("AddStaff");
//打开窗口
WindowManager.Show("AddStaff",new AddViewModel());
//MessageBox.Show("你点击了一个按钮");
//新增
//staffs.Add(new Staff() { Id = 3, Name = "小黄", address = "China", age = "19", gender = (Gender)0, Contactnumber = "15309878644" });
//修改
//staffs[0] = new Staff() { Id = 3, Name = "小黄", address = "China", age = "19", gender = (Gender)0, Contactnumber = "15309878644" };
//删除
//staffs.RemoveAt(1);
//清空全部;
// staffs.Clear();
});
}
public void Selectstaff()
{
string sql = "Select * from Staff";
SqlDataReader data = SqlCon.Reader(sql);
while (data.Read())
{
staffs.Add(new Staff() { Id = Convert.ToInt32(data["Id"]), Name = data["Name"].ToString(), age = data["age"].ToString(), gender = (Gender)Convert.ToInt32(data["gender"]), address = data["address"].ToString(), Contactnumber = data["Conrtactnumber"].ToString() });
}
}
private string mcontent ;
public string Mcontent
{
get { return mcontent; }
set { mcontent = value; }
}
private string title = "标题";
public string Title
{
get { return title; }
set { title = value; }
}
//搜索 SearchCommand
public ICommand SearchCommand { get; set; }
}
ViewModelUtil.cs
namespace WpfApp2.ViewModels
{
//INotifyPropertyChanged 通知客户端属性值以修改;
public class ViewModelUtil : INotifyPropertyChanged
{
//在属性值改变时发生;
public event PropertyChangedEventHandler? PropertyChanged;
public void RaisPropertyChanged(string propertyName )
{
if (propertyName != null)
{
//Invoke调用 初始化PropertyChangedEventArgs; propertyName 以更改属性的名称
PropertyChanged?.Invoke( this, new PropertyChangedEventArgs( propertyName ) );
}
}
}
}
RelayCommand.cs
namespace WpfApp2.ViewModels
{
public class RelayCommand : ICommand
{
//EventHandler 表示将处理没有事件数据的事件的方法。
public event EventHandler? CanExecuteChanged;
//封装具有单个参数且不返回值的方法;
private Action<object> _ExecuteAction;
//构造函数
public RelayCommand(Action<object> action)
{
_ExecuteAction= action;
}
public bool CanExecute(object? parameter)
{
return true;
}
public void Execute(object? parameter)
{
//Invoke 调用
_ExecuteAction?.Invoke(parameter);
}
}
}
访问数据库是通过Ado.Net 写的
public class SqlCon
{
public static readonly string SqlSouer = "Server=DESKTOP-09OGCCU;Initial Catalog=Met;User Id=sa1;Password=sa123";
///// <summary>
///// 新增
///// </summary>
///// <param name="sql">用于操作的SQL语句</param>
//public static string SqlAdd(string sql )
//{
// string msg = "";
// using (SqlConnection connection=new SqlConnection(SqlSouer))
// {
// //打开数据库
// connection.Open();
// //创建命令对象,指定要执行SQL语句与连接对象;
// SqlCommand sqlCommand = new SqlCommand(sql, connection);
// //执行,返回受影响行数;
// int rows=sqlCommand.ExecuteNonQuery();
// if(rows > 0)
// {
// msg = "执行成功";
// }
// ////关闭数据库
// //connection.Close();
// }
// return msg;
//}
///// <summary>
///// 查询
///// </summary>
///// <param name="sql"></param>
///// <param name="Met"></param>
///// <returns></returns>
//public static SqlDataReader Sqlinq(string sql,object Met)
//{
// Dictionary<string, string> result = new Dictionary<string, string>();
// using (SqlConnection connection = new SqlConnection(SqlSouer))
// {
// connection.Open();
// SqlCommand sqlCommand = new SqlCommand(sql, connection);
// //执行查询返回结果集;
// SqlDataReader reader = sqlCommand.ExecuteReader();
// return reader;
// }
//}
/// <summary>
/// 完成增,删,改
/// </summary>
/// <param name="sql">将要执行的sql</param>
/// <param name="ps">可变参数,指定sql中的参数</param>
/// <returns></returns>
/// params 可变参数 这里的可变是个数可变;
/// params 修饰在参数的前面且参数类型得是一维数组类型;
/// params 修饰的参数默认是可以不传递的
/// params 参数不能用ref或out修饰且不能手动给默认值;
public static int Execute(string sql,params SqlParameter[] ps)
{
foreach(SqlParameter p in ps)
{
if (p.Value == null)
{
p.Value=DBNull.Value;
}
}
using(SqlConnection conn = new SqlConnection(SqlSouer))
{
//打开连接
conn.Open();
//创建命令对象,指定sql与连接对象conn;
SqlCommand cmd =new SqlCommand(sql,conn);
//指定参数
if(ps != null) cmd.Parameters.AddRange(ps);
//执行sql 命令返回影响行数;
return cmd.ExecuteNonQuery();
}
}
/// <summary>
/// 完成查询;
/// </summary>
/// <param name="sql"></param>
/// <param name="ps"></param>
/// <returns></returns>
public static SqlDataReader Reader(String sql,params SqlParameter[] ps)
{
SqlConnection con = new SqlConnection(SqlSouer);
con.Open();
SqlCommand cmd=new SqlCommand(sql,con);
if(ps != null ) cmd.Parameters.AddRange(ps);
return cmd.ExecuteReader(CommandBehavior.CloseConnection);
}
}
上面的代码有注释,没有什么好说的(我自己也是刚刚学完,上面的代码相当于我的笔记) 标签：set,string,MVVM,get,实现,sql,new,WPF,public From： https://www.cnblogs.com/shengkun008/p/16931455.html