在本文中，您將開始創建根據 MVVM 模式構建的示例應用程序，并學習如何使用 Scaffolding Wizard。

獲取工具下載 - DevExpress v21.2

1. 創建一個新的WinForms應用程序。 要創建項目的數據模型，請添加一個新的模型文件夾并使用下面的代碼片段創建三個類——帳戶、交易和類別，這些類使用數據注釋屬性并要求將 System.ComponentModel.DataAnnotations 庫包含在您的項目中。

賬戶數據模型

C#

using System.ComponentModel.DataAnnotations;
namespace MVVMExpenses.DataModels {
public class Account {
[Key, Display(AutoGenerateField = false)]
public long ID { get; set; }
[Required, StringLength(30, MinimumLength = 4)]
[Display(Name = "ACCOUNT")]
public string Name { get; set; }
[DataType(DataType.Currency)]
[Display(Name = "AMOUNT")]
public decimal Amount { get; set; }
public override string ToString() {
return Name + " (" + Amount.ToString("C") + ")";
}
public virtual ICollection<Transaction> Transactions { get; set; }
}
}

VB.NET

Imports System.ComponentModel.DataAnnotations
Namespace MVVMExpenses.DataModels
Public Class Account
<Key, Display(AutoGenerateField := False)>
Public Property ID() As Long
<Required, StringLength(30, MinimumLength := 4), Display(Name := "ACCOUNT")>
Public Property Name() As String
<DataType(DataType.Currency), Display(Name := "AMOUNT")>
Public Property Amount() As Decimal
Public Overrides Function ToString() As String
Return Name & " (" & Amount.ToString("C") & ")"
End Function
Public Overridable Property Transactions() As ICollection(Of Transaction)
End Class
End Namespace

類別數據模型

C#

using System.ComponentModel.DataAnnotations;
namespace MVVMExpenses.DataModels {
public class Category {
[Key, Display(AutoGenerateField = false)]
public long ID { get; set; }
[Required, StringLength(30, MinimumLength = 5)]
[Display(Name = "CATEGORY")]
public string Name { get; set; }
[EnumDataType(typeof(TransactionType))]
[Display(Name = "TRANSACTION TYPE")]
public TransactionType Type { get; set; }
public override string ToString() {
return Name + " (" + Type.ToString() + ")";
}
public virtual ICollection<Transaction> Transactions { get; set; }
}
}

VB.NET

Namespace MVVMExpenses.DataModels
Public Class Category
<Key, Display(AutoGenerateField := False)>
Public Property ID() As Long
<Required, StringLength(30, MinimumLength := 5), Display(Name := "CATEGORY")>
Public Property Name() As String
<EnumDataType(GetType(TransactionType)), Display(Name := "TRANSACTION TYPE")>
Public Property Type() As TransactionType
Public Overrides Function ToString() As String
Return Name & " (" & Type.ToString() & ")"
End Function
Public Overridable Property Transactions() As ICollection(Of Transaction)
End Class
End Namespace

交易數據模型

C#

using System.ComponentModel.DataAnnotations;
namespace MVVMExpenses.DataModels {
public enum TransactionType {
Expense,
Income
}
public class Transaction {
[Key, Display(AutoGenerateField = false)]
public long ID { get; set; }
[Display(AutoGenerateField = false)]
public long AccountID { get; set; }
[Display(Name = "ACCOUNT")]
public virtual Account Account { get; set; }
[Display(AutoGenerateField = false)]
public long CategoryID { get; set; }
[Display(Name = "CATEGORY")]
public virtual Category Category { get; set; }
[DataType(DataType.Date)]
[Display(Name = "DATE")]
public DateTime Date { get; set; }
[DataType(DataType.Currency)]
[Display(Name = "AMOUNT")]
public decimal Amount { get; set; }
[DataType(DataType.MultilineText)]
[Display(Name = "COMMENT")]
public string Comment { get; set; }
}
}

VB.NET

Namespace MVVMExpenses.DataModels
Public Enum TransactionType
Expense
Income
End Enum
Public Class Transaction
<Key, Display(AutoGenerateField := False)>
Public Property ID() As Long
<Display(AutoGenerateField := False)>
Public Property AccountID() As Long
<Display(Name := "ACCOUNT")>
Public Overridable Property Account() As Account
<Display(AutoGenerateField := False)>
Public Property CategoryID() As Long
<Display(Name := "CATEGORY")>
Public Overridable Property Category() As Category
<DataType(DataType.Date), Display(Name := "DATE")>
Public Property [Date]() As Date
<DataType(DataType.Currency), Display(Name := "AMOUNT")>
Public Property Amount() As Decimal
<DataType(DataType.MultilineText), Display(Name := "COMMENT")>
Public Property Comment() As String
End Class
End Namespace

2. 跳轉到Visual Studio 的 Project 菜單并選擇 Manage NuGet Packages...菜單項，在在線存儲中搜索 Entity Framework 6 package，然后單擊 ‘Install’，請注意如果未安裝此 NuGet 包，您將無法在此示例應用程序中使用實體模型。

3. 添加以下 DbContext 類后代，它將用作 DevExpress Scaffolding Wizard 的上下文。

C#

using System.Data.Entity;
using MVVMExpenses.DataModels;

namespace MVVMExpenses.DataBase {
public class MyDbContext : System.Data.Entity.DbContext {
static MyDbContext() {
System.Data.Entity.Database.SetInitializer<MyDbContext>(null);
}
public DbSet<Account> Accounts { get; set; }
public DbSet<Category> Categories { get; set; }
public DbSet<Transaction> Transactions { get; set; }
}
}

VB.NET

Imports System.Data.Entity
Imports MVVMExpenses.DataModels

Namespace MVVMExpenses.DataBase
Public Class MyDbContext
Inherits System.Data.Entity.DbContext

Shared Sub New()
System.Data.Entity.Database.SetInitializer(Of MyDbContext)(Nothing)
End Sub
Public Property Accounts() As DbSet(Of Account)
Public Property Categories() As DbSet(Of Category)
Public Property Transactions() As DbSet(Of Transaction)
End Class
End Namespace

4. 在繼續下一步之前，構建您的項目并確保它編譯時沒有錯誤。 然后，在 Visual Studio 解決方案資源管理器中右鍵單擊您的項目并選擇 Add DevExpress Item - Data Model Scaffolding...（參見下圖）。 這將啟動 Scaffolding Wizard，它將生成完整的應用程序層次結構，包括來自數據上下文的 MVVM-ready DataModel。

注意：如果缺少此菜單項，請右鍵單擊您的項目并選擇默認的 Visual Studio Add - New Item... 選項。 在對話框中，選擇 DevExpress Template Gallery 并手動啟動 Scaffolding Wizard - 選擇 Data Model Scaffolding 選項卡（WinForms Data Models 組）并單擊右下角的 Run Wizard 按鈕。

在 Wizard 對話框中，選擇在第二步中創建的上下文，然后單擊 Next。 檢查所有必需的表和視圖，然后單擊Finish來啟動模型生成。

5. 結果，您將看到許多新文件、文件夾和類添加到您的應用程序中。

目前，只有向導生成的兩個文件夾值得一提 - 包含您的 CRUD 數據模型的 DataModel 文件夾和包含 DbContext 中每個表的 MVVM ViewModel 的 ViewModels 文件夾 - Account、Category 和 Transaction。 在接下來的課程中，您將學習如何為這些 ViewModel 創建 View。

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