如何通过t4生成自定义类？
我试图通过T4生成以下代码。
using System; using MyDAL; namspace Test { // Select... public partial class MyCustomer { public int id { get ;set;} public string name { get ;set;} public string surname { get ;set;} public MyCustomer() { } public List GetById(int id) { // do something... } } // Delete,Update,Save public partial class MyCustomer { public bool Save(new MyCustomer) { // do something... } public bool delete(int id) { // do something... } public bool Update(int id) { // do something... } } } 到目前为止我的T4模板：
namespace DbClasses { }
我不确定你面临的问题是什么：但你的T4代码没有任何问题。 第二个类中Save方法的签名是新的，这是一个错误：
public bool Save(new MyCustomer)
应该
public bool Save(MyCustomer customer)
此外，GetById应返回一个元素而不是列表。
我通过为Table，Column等编写虚拟类来尝试编写的代码而不连接到数据库，并且您编写的T4代码没有任何问题，只是根据您的要求，您编写的代码不会生成部分类，而不是它创建属性。 它只是为每个具有公共字段（不是属性）的表创建一个非部分类。 如果你想生成部分类和属性（和方法），你就是正确的方向（我添加了标签和换行符，使其在生成的文件中看起来很漂亮，你可以按Ctrl + K，Ctrl + D那里重新格式化它虽然：
<# foreach (Table tablo in tables) { //start class WriteLine("public partial class My" +tablo.Name+"\n{"); foreach (Column column in tablo.Columns) { if(column.DataType.Name=="nvarchar") WriteLine("\tpublic string " + column.Name+"{get; set;}"); else WriteLine("\tpublic int " + column.Name+"{get; set;}"); } //output the contructor WriteLine("\tpublic My" + tablo.Name + "()\n\t{\n\t\t//constructor\n\t}" ); WriteLine("\tpublic List<" + tablo.Name + "> GetById(int id)\n\t{\n\t\t// do something\n\t}"); //end class WriteLine("}"); //output comment and start class WriteLine("//Delete,Update,Save"); WriteLine("public partial class My" +tablo.Name+"\n{"); WriteLine("\tpublic bool Save(My" + tablo.Name + " " + tablo.Name + ")\n\t{\n\t\t// do something\n\t}"); WriteLine("\tpublic bool Delete(int id)\n\t{\n\t\t// do something\n\t}"); WriteLine("\tpublic bool Update(int id)\n\t{\n\t\t// do something\n\t}"); WriteLine("}"); } #>
它并不完整，但也许下面的T4可以作为一些灵感。
这是如何使用它：
using (var sqlConnection = new SqlConnection (@"Data Source=localhost\SQLExpress;Initial Catalog=MinTest;Integrated Security=True")) using (var sqlCommand = sqlConnection.CreateCommand ()) { sqlConnection.Open (); var customers = sqlCommand.Get_Customer (Id:10, CompId:20).ToArray (); foreach (var customer in customers) { Console.WriteLine (customer.Id); Console.WriteLine (customer.CompId); Console.WriteLine (customer.FirstName); Console.WriteLine (customer.LastName); Console.WriteLine (customer.OrgNo); } var deleteCount = sqlCommand.Delete_Customer (Id:20, CompId:20); Console.WriteLine ("Deleted rows: {0}", deleteCount); Console.ReadKey (); }
T4：
<#@ template language = "C#" #> <#@ assembly name = "Microsoft.SqlServer.Management.Sdk.Sfc" #> <#@ assembly name = "Microsoft.SqlServer.ConnectionInfo" #> <#@ assembly name = "Microsoft.SqlServer.Smo" #> <#@ assembly name = "System.Core" #> <#@ assembly name = "System.XML" #> <#@ import namespace = "Microsoft.SqlServer.Management.Smo" #> <#@ import namespace = "System.Collections.Generic" #> <#@ import namespace = "System.Linq" #> <#@ import namespace = "System.Text" #> // ReSharper disable InconsistentNaming // ReSharper disable PartialTypeWithSinglePart <# // Update SQL Server and namespace var nameSpace = "MyNameSpace"; var server = new Server (@"localhost\SQLExpress"); var database = new Database (server,"MyDB"); var maxTables = int.MaxValue; database.Refresh (); #> namespace <#=nameSpace#> { using System; using System.Collections.Generic; using System.Data.SqlClient; static partial class Extensions { static int Lookup (Dictionary dic, string key) { int value; return dic.TryGetValue (key, out value) ? value : -1; } static byte[] GetByteArray (this SqlDataReader reader, int index) { var byteLength = reader.GetBytes (index, 0, null, 0, 0); var bytes = new byte[byteLength]; reader.GetBytes (index, 0, bytes, 0, bytes.Length); return bytes; } <# foreach (var table in database.Tables.OfType ().Take (maxTables)) { #> // -------------------------------------------------------------------- // Deletes <#=table.Name#> // -------------------------------------------------------------------- public static int Delete_<#=table.Name#> ( this SqlCommand command <# foreach (var column in table.Columns.OfType ().Where (c => c.InPrimaryKey)) { #> , <#=GetType (column)#> <#=column.Name#> <# } #> ) { if (command != null) { command.CommandText = "DELETE FROM <#=table.Schema#>.<#=table.Name#> <#=GetWhereClause (table)#>"; command.Parameters.Clear (); <# foreach (var column in table.Columns.OfType ().Where (c => c.InPrimaryKey)) { #> command.Parameters.AddWithValue (@"<#=column.Name#>", <#=column.Name#>); <# } #> return command.ExecuteNonQuery (); } else { return 0; } } // -------------------------------------------------------------------- // -------------------------------------------------------------------- // Gets <#=table.Name#> // -------------------------------------------------------------------- public static IEnumerable<<#=table.Name#>> Get_<#=table.Name#> ( this SqlCommand command <# foreach (var column in table.Columns.OfType ().Where (c => c.InPrimaryKey)) { #> , <#=GetType (column)#> <#=column.Name#> <# } #> ) { if (command != null) { command.CommandText = "SELECT * FROM <#=table.Schema#>.<#=table.Name#> <#=GetWhereClause (table)#>"; command.Parameters.Clear (); <# foreach (var column in table.Columns.OfType ().Where (c => c.InPrimaryKey)) { #> command.Parameters.AddWithValue (@"<#=column.Name#>", <#=column.Name#>); <# } #> using (var reader = command.ExecuteReader ()) { foreach (var row in reader.To_<#=table.Name#> ()) { yield return row; } } } } // -------------------------------------------------------------------- // -------------------------------------------------------------------- // Deserializes a <#=table.Name#> // -------------------------------------------------------------------- public static IEnumerable<<#=table.Name#>> To_<#=table.Name#> (this SqlDataReader reader) { if (reader != null) { var fieldCount = reader.FieldCount; var dictionary = new Dictionary (); for (var iter = 0; iter < fieldCount; ++iter) { dictionary[reader.GetName (iter)] = iter; } while (reader.Read ()) { var instance = new <#=table.Name#> (); <# foreach (var column in table.Columns.OfType ()) { #> { var index = Lookup (dictionary, "<#=column.Name#>"); if (index > -1) { instance.<#=column.Name #> = reader.<#=GetGetter (column)#> (index); } } <# } #> yield return instance; } } } // -------------------------------------------------------------------- <# } #> } <# foreach (var table in database.Tables.OfType ().Take (maxTables)) { #> // ------------------------------------------------------------------------ // Table: <#=table.Name#> // ------------------------------------------------------------------------ partial class <#=table.Name#> { <# foreach (var column in table.Columns.OfType ()) { #> // <#=column.DataType.Name#> (<#=column.Nullable#>, <#=column.DataType.MaximumLength#>, <#=column.DataType.SqlDataType#>) public <#=GetType (column)#> <#=column.Name#> {get;set;} <# } #> } // ------------------------------------------------------------------------ <# } #> } <#+ sealed class DataTypeDescriptor { public readonly bool IsValueType; public readonly string Type; public readonly string Getter; public DataTypeDescriptor ( bool isValueType, string type, string getter = null ) { IsValueType = isValueType; Type = type; Getter = getter ?? ("Get" + type); } } readonly static Dictionary s_typeDescriptors = new Dictionary () { // Unsupported: // ------------ // None, // UserDefinedDataType, // UserDefinedDataType, // XML, // SysName, // UserDefinedTableType, // HierarchyId, // Geometry, // Geography {SqlDataType.BigInt , new DataTypeDescriptor (true , "Int64" )}, {SqlDataType.Binary , new DataTypeDescriptor (true , "Byte" )}, {SqlDataType.Bit , new DataTypeDescriptor (true , "Boolean" )}, {SqlDataType.Char , new DataTypeDescriptor (false , "String" )}, {SqlDataType.DateTime , new DataTypeDescriptor (true , "DateTime" )}, {SqlDataType.Decimal , new DataTypeDescriptor (true , "Decimal" )}, {SqlDataType.Float , new DataTypeDescriptor (true , "Double" )}, {SqlDataType.Image , new DataTypeDescriptor (false , "byte[]" , "GetByteArray" )}, {SqlDataType.Int , new DataTypeDescriptor (true , "Int32" )}, {SqlDataType.Money , new DataTypeDescriptor (true , "Decimal" )}, {SqlDataType.NChar , new DataTypeDescriptor (false , "String" )}, {SqlDataType.NText , new DataTypeDescriptor (false , "String" )}, {SqlDataType.NVarChar , new DataTypeDescriptor (false , "String" )}, {SqlDataType.NVarCharMax , new DataTypeDescriptor (false , "String" )}, {SqlDataType.Real , new DataTypeDescriptor (true , "Double" )}, {SqlDataType.SmallDateTime , new DataTypeDescriptor (true , "DateTime" )}, {SqlDataType.SmallInt , new DataTypeDescriptor (true , "Int16" )}, {SqlDataType.SmallMoney , new DataTypeDescriptor (true , "Decimal" )}, {SqlDataType.Text , new DataTypeDescriptor (false , "String" )}, {SqlDataType.Timestamp , new DataTypeDescriptor (false , "byte[]" , "GetByteArray" )}, {SqlDataType.TinyInt , new DataTypeDescriptor (true , "Byte" )}, {SqlDataType.UniqueIdentifier , new DataTypeDescriptor (false , "byte[]" , "GetByteArray" )}, {SqlDataType.VarBinary , new DataTypeDescriptor (false , "byte[]" , "GetByteArray" )}, {SqlDataType.VarBinaryMax , new DataTypeDescriptor (false , "byte[]" , "GetByteArray" )}, {SqlDataType.VarChar , new DataTypeDescriptor (false , "String" )}, {SqlDataType.VarCharMax , new DataTypeDescriptor (false , "String" )}, {SqlDataType.Variant , new DataTypeDescriptor (false , "object" , "GetValue")}, {SqlDataType.Numeric , new DataTypeDescriptor (true , "Decimal" )}, {SqlDataType.Date , new DataTypeDescriptor (true , "DateTime" )}, {SqlDataType.Time , new DataTypeDescriptor (true , "TimeSpan" )}, {SqlDataType.DateTimeOffset , new DataTypeDescriptor (true , "DateTimeOffset" )}, {SqlDataType.DateTime2 , new DataTypeDescriptor (true , "DateTime" )}, }; static string GetGetter (Column column) { var dataType = column.DataType; DataTypeDescriptor descriptor; if (!s_typeDescriptors.TryGetValue (dataType.SqlDataType, out descriptor)) { return "Error__Unsupported_Type_" + dataType.SqlDataType ; } return descriptor.Getter; } static string GetType (Column column) { var dataType = column.DataType; DataTypeDescriptor descriptor; if (!s_typeDescriptors.TryGetValue (dataType.SqlDataType, out descriptor)) { return "Error__Unsupported_Type_" + dataType.SqlDataType ; } if (column.Nullable && descriptor.IsValueType) { return descriptor.Type + "?"; } return descriptor.Type; } static string GetWhereClause (Table table) { var sb = new StringBuilder ("WHERE "); var first = true; foreach (var column in table.Columns.OfType ().Where (c => c.InPrimaryKey)) { if (first) { first = false; } else { sb.Append (" AND "); } sb.AppendFormat ("{0} = @{0}", column.Name); } return sb.ToString (); } #>