什么是MVVM架构和数据绑定？

<ComboBox MaxWidth="150" Width="100" SelectedValue="{Binding StrCMBselectValue, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" DisplayMemberPath="Text"                                                SelectedValuePath="Value" ItemsSource="{Binding LstCSGDownLevelID, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" />

<DataGrid ColumnWidth="*" SelectedItem="{Binding CurrentSelectItem}"  ItemsSource="{Binding CsGroupsAll}" AutoGenerateColumns="False"  IsReadOnly="True" >                                  <DataGrid.Columns>                                      <DataGridTextColumn Header="分组编号" Binding="{Binding Code}" />                                      <DataGridTextColumn Header="分组名称" Binding="{Binding Name}" />                                  </DataGrid.Columns>                              </DataGrid>

using HeYin.ERP.DataModels;using HeYin.ERP.IServices;using HeYin.ERP.Models;using HeYin.ERP.Services;using Microsoft.Practices.Prism.Commands;using System;using System.Collections.Generic;using System.Collections.ObjectModel;using System.Windows;using System.Text.RegularExpressions;using System.Windows.Controls;namespace HeYin.ERP.Client.ViewModels.Customer  {class CusGroupEditViewModel : BaseViewModel      {private bool bIsAdd = false;            ICusGroupService CGS;  //调用IService接口#region Properties 属性private Guid gCsGroupID = Guid.Empty;//All CusGroupprivate List<CusGroup> csGroupsAll;public List<CusGroup> CsGroupsAll          {get { return csGroupsAll; }set{                  csGroupsAll = value; //设定值OnPropertyChanged("CsGroupsAll"); //在属性更改后，通知            }          }private List<CusGroup> csGroupsMinPrestore;public List<CusGroup> CsGroupsAllMinPrestore          {get { return csGroupsMinPrestore; }set{                  csGroupsMinPrestore = value; //设定值OnPropertyChanged("CsGroupsAllMinPrestore"); //在属性更改后，通知            }          }//CusGroup对象private CusGroup csGroup;public CusGroup CsGroup          {get { return csGroup; }set{ csGroup = value;                  OnPropertyChanged("CsGroup"); }          }/// <summary>/// /// </summary>private string strCMBselectValue;public string StrCMBselectValue          {get { return strCMBselectValue; }set{if (value != null)                  {                      strCMBselectValue = value;                      OnPropertyChanged("StrCMBselectValue");                  }              }          }/// <summary>/// ComboBoxDataModel：作为一个ComboBox的对象，可以理解为数据源/// </summary>private ObservableCollection<ComboBoxDataModel> lstCSGDownLevelID;public ObservableCollection<ComboBoxDataModel> LstCSGDownLevelID          {get { return lstCSGDownLevelID; }set{                  lstCSGDownLevelID = value;                  OnPropertyChanged("LstCSGDownLevelID");              }          }//DataGrid当前选择对象private CusGroup currentSelectItem;public CusGroup CurrentSelectItem          {get { return currentSelectItem; }set{                  currentSelectItem = value;                    GetCutCmbSelect(value);              }          }private int errorCount;public int ErrorCount { get => errorCount; set => errorCount = value; }#endregion#region Commandspublic DelegateCommand<string> BtnChangedCommand { get; set; }public DelegateCommand<CusGroup> TxtChangedCommand { get; set; }        #endregionpublic CusGroupEditViewModel()          {              CGS = new CusGroupService();              CsGroupsAll = new List<CusGroup>();              csGroup = new CusGroup();              LstCSGDownLevelID = new ObservableCollection<ComboBoxDataModel>();              BtnChangedCommand = new DelegateCommand<string>(MenuClick);              TxtChangedCommand = new DelegateCommand<CusGroup>(ChangeCMBValue);                GetAllCusGroups();          }#region ButtonClickprivate void MenuClick(string strMessage)          {if (string.IsNullOrEmpty(strMessage)) return;if (CsGroup == null) return;switch (strMessage)              {case "btnCusGroupSave":                      Save();break;case "btnCusGroupAdd":                      Add();break;case "btnCusGroupDelete":                      Delete();break;              }          }#endregion ButtonClick#region motheds/// <summary>/// 获取全部Group/// </summary>private void GetAllCusGroups()          {//获取满足条件的客户分组信息            CsGroupsAll.Clear();              CsGroupsAll = CGS.Get(s => s.IsDelete == 0);                GetAllCMBItems();//给降档分组下拉框赋值if ((gCsGroupID == null || gCsGroupID == Guid.Empty) && CsGroupsAll.Count > 0)                  CsGroup = CsGroupsAll[0];    //给基础信息等赋值StrCMBselectValue = CsGroup.DownLevelID.ToString();//设置降档分组默认值        }/// <summary>/// 添加/// </summary>/// <param name="cg"></param>private void AddCusGroup(CusGroup cg)          {              cg.ID = Guid.NewGuid(); //新建分组GUIDcg.IsDelete = 0;        //默认为0：不删除cg.CreateBy = App.GetCurrentUserId();//创建人员关联员工 GUIDcg.CreateTime = DateTime.Now;  //初始化创建时间，应该使用服务器当前时间bool c = CGS.Add(cg);if (c)              {                  MessageBox.Show(string.Format("创建新组别【{0}】成功！", CsGroup.Name), "提示", MessageBoxButton.OK, MessageBoxImage.Information);                  GetAllCusGroups();                  bIsAdd = false;              }          }/// <summary>/// 修改/// </summary>/// <param name="cg"></param>private void UpdateCusGroup(CusGroup cg)          {              bIsAdd = false;                cg.UpdateTime = DateTime.Now;              cg.UpdateBy = App.GetCurrentUserId();//更新人员关联员工 GUIDstring[] str = { "UpdateTime", "UpdateBy" };bool b = CGS.Edit(cg, str);if (b)              {                  MessageBox.Show("更改组别【成功】！", "提示", MessageBoxButton.OK, MessageBoxImage.Information);                  GetAllCusGroups();              }          }/// <summary>///删除方法（实为更新）/// </summary>/// <param name="cg"></param>private void DeleteCusGroup(CusGroup cg)          {              cg.IsDelete = 1; //更改数据库删除标志cg.UpdateTime = DateTime.Now;  //更新删除时间cg.UpdateBy = App.GetCurrentUserId();//更新人员关联员工 GUIDstring[] str = { "UpdateTime", "IsDelete", "UpdateBy" };bool b = CGS.Edit(cg, str);if (b)              {//MessageBox.Show(string.Format("已删除组别【{0}】！", CsGroup.Name), "提示", MessageBoxButton.OK, MessageBoxImage.Information);                GetAllCusGroups();                  CsGroup = new CusGroup(); //清空对象bIsAdd = true;              }          }/// <summary>/// 插入和更新方法调用/// </summary>private void Save()          {if (ErrorCount > 0)              {//判断必填数据是否为空：为空则提示MessageBox.Show("请核对所填数据", "提示", MessageBoxButton.YesNo, MessageBoxImage.Information);return;              }if (bIsAdd)                  AddCusGroup(CsGroup);elseUpdateCusGroup(CsGroup);          }/// <summary>/// 获取降档分组下拉列表的值，并指定默认值/// </summary>/// <param name="value"></param>private void GetCutCmbSelect(CusGroup value)          {              bIsAdd = false;//点击新增后，再选择列表的逻辑if (value != null)              {                  CsGroup = CGS.GetById(value.ID);//查找出当前选中的对象gCsGroupID = CsGroup.ID;        //保存当前选择对象的GUIDif (CsGroup != null)                  {if (CsGroup.DownLevelID.HasValue)                      {//如果降档ID有值，则默认显示，如果没有，则显示为空GetExceptCMBSelect();//刷新下拉列表，先刷新，再赋值给默认值StrCMBselectValue = CsGroup.DownLevelID.ToString();                      }else{                          LstCSGDownLevelID.Clear();                          StrCMBselectValue = string.Empty;                      }                  }              }          }private void Add()          {              bIsAdd = true;//点击新建分组时，重新获取所有降档ID对应的中文名            GetAllCMBItems();                CsGroup = new CusGroup();          }private void Delete()          {if (this.CsGroup.ID == Guid.Empty || CsGroup.ID == null)                  MessageBox.Show("请选择要删除组别", "提示", MessageBoxButton.OK, MessageBoxImage.Information);else{                  MessageBoxResult msgResult = MessageBox.Show(string.Format("确定要删除分组【{0}】吗？", CsGroup.Name), "提示", MessageBoxButton.YesNo, MessageBoxImage.Information);if (msgResult == MessageBoxResult.Yes)                      DeleteCusGroup(CsGroup);              }          }/// <summary>/// 排除当前列的降档ID和对应的Name/// </summary>private void GetExceptCMBSelect()          {              LstCSGDownLevelID.Clear();              CsGroupsAllMinPrestore = CGS.Get(s => s.IsDelete == 0 && s.MinPrestore <= CsGroup.MinPrestore);foreach (var iDlID in CsGroupsAllMinPrestore)              {if (iDlID.ID != CsGroup.ID) //去除当前选择ID对应的NameLstCSGDownLevelID.Add(new ComboBoxDataModel() { Value = iDlID.ID.ToString(), Text = iDlID.Name });              }          }/// <summary>/// 获取列表中所有降档ID和对应的Name/// </summary>private void GetAllCMBItems()          {              LstCSGDownLevelID.Clear();foreach (var iDlID in CsGroupsAll)              {                  LstCSGDownLevelID.Add(new ComboBoxDataModel() { Value = iDlID.ID.ToString(), Text = iDlID.Name });              }          }private void ChangeCMBValue(CusGroup cgMinPrestore)          {              LstCSGDownLevelID.Clear();              List<CusGroup> lstTextChange = new List<CusGroup>();              lstTextChange = CGS.Get(s => s.MinPrestore < cgMinPrestore.MinPrestore);foreach (var iDlID in lstTextChange)              {                  LstCSGDownLevelID.Add(new ComboBoxDataModel() { Value = iDlID.ID.ToString(), Text = iDlID.Name });              }          }public void SizeChangedCommand(object obj, SizeChangedEventArgs e)          {                MessageBox.Show("日了狗");            }#endregion}  }

<client:BaseWindow x:Class="HeYin.ERP.Client.Views.Customer.CusGroupEditWindow"          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"          xmlns:Interaction="http://schemas.microsoft.com/expression/2010/interactions"          xmlns:Interactivity="http://schemas.microsoft.com/expression/2010/interactivity"          xmlns:CommonValidation="clr-namespace:HeYin.ERP.Common.Validation;assembly=HeYin.ERP.Common"          xmlns:client="clr-namespace:HeYin.ERP.Client"          mc:Ignorable="d"          x:Name="CusGroupWindow"           Title="客户分组" Height="500" Width="800"           WindowStartupLocation="CenterOwner"          Loaded="Window_Loaded"           MaxboxEnable="True"           MinboxEnable="False" >        <Interactivity:Interaction.Triggers>          <Interactivity:EventTrigger EventName="SizeChanged">              <Interaction:CallMethodAction TargetObject="{Binding}" MethodName="SizeChangedCommand"/>          </Interactivity:EventTrigger>      </Interactivity:Interaction.Triggers>        <Grid>            <Grid.RowDefinitions>              <RowDefinition Height="*" />              <RowDefinition Height="50" />          </Grid.RowDefinitions>            <Grid Grid.Row="0">              <Grid.ColumnDefinitions>                  <ColumnDefinition Width="1*"/>                  <ColumnDefinition Width="2*"/>              </Grid.ColumnDefinitions>                <!-- Left -->              <Grid  Margin="5,0,5,5">                  <GroupBox Name="gbGroupData">                      <GroupBox.HeaderTemplate>                          <DataTemplate>                              <WrapPanel Margin="{StaticResource WrapPanelMarginForInfo}">                                  <TextBlock Text="客户分组"  Height="20" />                                  <Button Width="20" Height="20" Margin="50,0,0,0"                                           Command="{Binding DataContext.BtnChangedCommand,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=GroupBox}}"                                          CommandParameter="btnCusGroupAdd"                                          Visibility="{Binding SaveVisibility,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">                                      <Image Source="..\..\Resources\Images\16\Add.png" />                                  </Button>                                    <Button Width="20" Height="20" Margin="10,0,0,0"                                           Command="{Binding  DataContext.BtnChangedCommand,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=GroupBox}}"                                           CommandParameter="btnCusGroupDelete"                                          Visibility="{Binding SaveVisibility,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">                                      <Image Source="..\..\Resources\Images\16\Clear.png" />                                  </Button>                              </WrapPanel>                          </DataTemplate>                      </GroupBox.HeaderTemplate>                        <Grid>                          <Grid Grid.Row="1">                              <DataGrid ColumnWidth="*" SelectedItem="{Binding CurrentSelectItem}"  ItemsSource="{Binding CsGroupsAll}" AutoGenerateColumns="False"  IsReadOnly="True" >                                  <DataGrid.Columns>                                      <DataGridTextColumn Header="分组编号" Binding="{Binding Code}" />                                      <DataGridTextColumn Header="分组名称" Binding="{Binding Name}" />                                  </DataGrid.Columns>                              </DataGrid>                          </Grid>                      </Grid>                  </GroupBox>              </Grid>                <!-- Right -->              <Grid Grid.Column="1" Margin="5">                  <Grid.RowDefinitions>                      <RowDefinition Height="*"/>                      <RowDefinition Height="100"/>                      <RowDefinition Height="130"/>                  </Grid.RowDefinitions>                    <!-- 基础信息 -->                  <Grid>                      <GroupBox>                          <GroupBox.Header>                              <TextBlock Text="基础信息" Height="20"/>                          </GroupBox.Header>                            <StackPanel>                              <Grid Margin="0,10">                                  <Grid.ColumnDefinitions>                                      <ColumnDefinition Width="*" />                                      <ColumnDefinition Width="*" />                                  </Grid.ColumnDefinitions>                                    <TextBox  Visibility="Collapsed" x:Name="tbErrorCount" Text="{Binding ErrorCount, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"></TextBox>                                  <WrapPanel Margin="{StaticResource WrapPanelMarginForInfo}">                                      <TextBlock Width="60" Margin="{StaticResource TextBlockMarginForMostLeft}"><Run Text="分组编号" /></TextBlock>                                      <TextBox Name="txtCusGropCrod" MaxWidth="150" Width="100"                                                ToolTip="{Binding RelativeSource={RelativeSource self},Path=(Validation.Errors).CurrentItem.ErrorContent}" Validation.Error="Validation_Error">                                          <TextBox.Text>                                              <Binding Path="CsGroup.Code" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" ValidatesOnDataErrors="True" NotifyOnValidationError="True">                                                  <Binding.ValidationRules>                                                      <ExceptionValidationRule></ExceptionValidationRule>                                                      <CommonValidation:RequiredValidationRule MaxLenth="15" ErrorMessage="分组编号" IsRequired="True" ValidatesOnTargetUpdated="True" />                                                  </Binding.ValidationRules>                                              </Binding>                                          </TextBox.Text>                                      </TextBox>                                  </WrapPanel>                                    <WrapPanel Margin="{StaticResource WrapPanelMarginForInfo}" Grid.Column="1">                                      <TextBlock Text="分组名称" Width="60" Margin="{StaticResource TextBlockMarginForMostLeft}"/>                                      <TextBox Name="txtCusGropName"  MaxWidth="150" Width="100"                                                ToolTip="{Binding RelativeSource={RelativeSource self},Path=(Validation.Errors).CurrentItem.ErrorContent}" Validation.Error="Validation_Error">                                          <TextBox.Text>                                              <Binding Path="CsGroup.Name" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" ValidatesOnDataErrors="True" NotifyOnValidationError="True">                                                  <Binding.ValidationRules>                                                      <ExceptionValidationRule></ExceptionValidationRule>                                                      <CommonValidation:RequiredValidationRule MaxLenth="15" ErrorMessage="分组名称" IsRequired="True" ValidatesOnTargetUpdated="True" />                                                  </Binding.ValidationRules>                                              </Binding>                                          </TextBox.Text>                                      </TextBox>                                  </WrapPanel>                              </Grid>                                <Grid>                                  <WrapPanel Margin="{StaticResource WrapPanelMarginForInfo}">                                      <TextBlock Margin="{StaticResource TextBlockMarginForMostLeft}" Width="60" VerticalAlignment="Center"><Run Text="分组描述" /></TextBlock>                                        <TextBox x:Name="tbRemark"  TextWrapping="Wrap" AcceptsReturn="True" VerticalScrollBarVisibility="Visible" Width="400" Height="90"                               ToolTip="{Binding RelativeSource={RelativeSource self},Path=(Validation.Errors).CurrentItem.ErrorContent}" Validation.Error="Validation_Error">                                          <TextBox.Text>                                              <Binding Path="CsGroup.Description" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged" ValidatesOnDataErrors="True" NotifyOnValidationError="True">                                                  <Binding.ValidationRules>                                                      <ExceptionValidationRule></ExceptionValidationRule>                                                      <CommonValidation:RequiredValidationRule MaxLenth="300" ErrorMessage="分组描述"  ValidatesOnTargetUpdated="True" />                                                  </Binding.ValidationRules>                                              </Binding>                                          </TextBox.Text>                                      </TextBox>                                  </WrapPanel>                              </Grid>                          </StackPanel>                      </GroupBox>                  </Grid>                    <!-- 消费相关 -->                  <Grid Grid.Row="1" Margin="0,10,0,10">                      <Grid>                          <GroupBox>                              <GroupBox.Header>                                  <TextBlock Text="消费相关"/>                              </GroupBox.Header>                                <Grid Margin="0,10">                                  <Grid.ColumnDefinitions>                                      <ColumnDefinition Width="*"/>                                      <ColumnDefinition Width="*"/>                                  </Grid.ColumnDefinitions>                                    <WrapPanel Margin="{StaticResource WrapPanelMarginForInfo}">                                      <TextBlock Text="消费积分" Width="60" Height="20" Margin="{StaticResource TextBlockMarginForMostLeft}" />                                      <TextBox Name="txtCusGropJF" MaxWidth="150" Width="100" Text="{Binding CsGroup.PointConversion, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" />                                  </WrapPanel>                                  <WrapPanel Grid.Column="1" Margin="{StaticResource WrapPanelMarginForInfo}"  HorizontalAlignment="Left" VerticalAlignment="Center">                                      <CheckBox Name="cbCash" Margin="0,0,5,0" IsChecked="{Binding CsGroup.IsCash}"/>                                      <TextBlock Text="开通预存或储值时禁止现金交易" />                                  </WrapPanel>                              </Grid>                          </GroupBox>                      </Grid>                  </Grid>                    <!-- 预存相关 -->                  <Grid Grid.Row="2">                      <GroupBox>                          <GroupBox.Header>                              <TextBlock Text="预存相关"/>                          </GroupBox.Header>                            <StackPanel>                              <Grid Margin="0,10">                                  <Grid.ColumnDefinitions>                                      <ColumnDefinition Width="*"/>                                      <ColumnDefinition Width="*"/>                                  </Grid.ColumnDefinitions>                                    <WrapPanel Margin="{StaticResource WrapPanelMarginForInfo}">                                      <TextBlock Width="80" Margin="{StaticResource TextBlockMarginForMostLeft}" ><Run Text="预存最低充值"/></TextBlock>                                      <TextBox MaxWidth="150" Width="100" Text="{Binding CsGroup.MinPrestore, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" />                                  </WrapPanel>                                  <WrapPanel Grid.Column="1" Margin="{StaticResource WrapPanelMarginForInfo}">                                      <TextBlock Width="80" Text="金额低缺报警" Margin="{StaticResource TextBlockMarginForMostLeft}" />                                      <TextBox MaxWidth="550" Width="100" Text="{Binding CsGroup.Alarm,Mode=TwoWay}" />                                  </WrapPanel>                              </Grid>                                <Grid Margin="0,5">                                  <WrapPanel Margin="{StaticResource WrapPanelMarginForInfo}">                                      <TextBlock Width="190" Text="预存金额未达到最低要求时降档至" Margin="{StaticResource TextBlockMarginForMostLeft}"/>                                      <ComboBox MaxWidth="150" Width="100" SelectedValue="{Binding StrCMBselectValue, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" DisplayMemberPath="Text"                                                SelectedValuePath="Value" ItemsSource="{Binding LstCSGDownLevelID, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" />                                  </WrapPanel>                              </Grid>                          </StackPanel>                      </GroupBox>                  </Grid>              </Grid>          </Grid>            <!-- bottom -->          <Grid Grid.Row="2">              <WrapPanel HorizontalAlignment="Center" VerticalAlignment="Center" Margin="{StaticResource WrapPanelMarginForInfo}">                  <Button Margin="1" Command="{Binding BtnChangedCommand}" CommandParameter="btnCusGroupSave" Background="#fc8530" Style="{StaticResource SaveButtonStyle}"                          Visibility="{Binding SaveVisibility,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" >                      <TextBlock  Text="保存"  FontWeight="Bold" FontSize="16"></TextBlock>                  </Button>              </WrapPanel>          </Grid>      </Grid>  </client:BaseWindow>