In ASP. NET, Entity classes are generated based on anonymous classes, datatable, and SQL statements.

In ASP. NET, Entity classes are generated based on anonymous classes, datatable, and SQL statements.

This article mainly introduces how to generate entity classes based on anonymous classes, datatable, and SQL in ASP. NET. This small tool class is very practical and easy to use. For more information, see

These situations may occur during development:

1. The anonymous objects queried by EF or LINQ are not convenient to call in other places, and they are also lazy to manually create object classes.

2. You need to create a class to reflect objects through datatable.

3. You also need to create a class for the entities returned by SQL statements.

4. If you want to write a template through the Code Generator, you need to install or do not want to generate a bunch of unused classes.

To solve the above inconvenience, I encapsulated an entity generation class, which can be thrown into the program for arbitrary calls.

Encapsulation class:

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Using System; Using System. Collections. Generic; Using System. Linq; Using System. Text; Using System. Data; Using System. Data. SqlClient; Using System. Text. RegularExpressions;   Namespace SyntacticSugar { /// <Summary> /// ** Description: entity generation class /// ** Founding Date: /// ** Modification time :- /// ** Prepared by sunkaixuan /// ** Qq: 610262374 welcome to the exchange, joint improvement, naming syntax, and other poorly written areas. You are welcome to give valuable suggestions. /// </Summary> Public class ClassGenerating { /// <Summary> /// Obtain the object class String Based on the anonymous class /// </Summary> /// <Param name = "entity"> anonymous object </param> /// <Param name = "className"> generated class name </param> /// <Returns> </returns> Public static string DynamicToClass (object entity, string className) { StringBuilder reval = new StringBuilder (); StringBuilder propertiesValue = new StringBuilder (); Var propertiesObj = entity. GetType (). GetProperties (); String replaceGuid = Guid. NewGuid (). ToString (); String nullable = string. Empty; Foreach (var r in propertiesObj) {   Var type = r. PropertyType; If (type. IsGenericType & type. GetGenericTypeDefinition () = typeof (Nullable <> )) { Type = type. GetGenericArguments () [0]; Nullable = "? "; } If (! Type. Namespace. Contains ("System. Collections. Generic ")) { PropertiesValue. AppendLine (); String typeName = ChangeType (type ); PropertiesValue. AppendFormat ("public {0} {3} {1} {2}", typeName, r. Name, "{get; set ;}", nullable ); PropertiesValue. AppendLine (); } }   Reval. AppendFormat (@" Public class {0 }{{ {1} }} ", ClassName, propertiesValue );     Return reval. ToString (); }     /// <Summary> /// Obtain the object class String Based on the DataTable /// </Summary> /// <Param name = "SQL"> </param> /// <Param name = "className"> </param> /// <Returns> </returns> Public static string DataTableToClass (DataTable dt, string className) { StringBuilder reval = new StringBuilder (); StringBuilder propertiesValue = new StringBuilder (); String replaceGuid = Guid. NewGuid (). ToString (); Foreach (DataColumn r in dt. Columns) { PropertiesValue. AppendLine (); String typeName = ChangeType (r. DataType ); PropertiesValue. AppendFormat ("public {0} {1} {2}", typeName, r. ColumnName, "{get; set ;}"); PropertiesValue. AppendLine (); } Reval. AppendFormat (@" Public class {0 }{{ {1} }} ", ClassName, propertiesValue );     Return reval. ToString (); }   /// <Summary> /// Obtain the object class String Based on the SQL statement /// </Summary> /// <Param name = "SQL"> SQL statement </param> /// <Param name = "className"> generated class name </param> /// <Param name = "server"> service name </param> /// <Param name = "database"> database name </param> /// <Param name = "uid"> account </param> /// <Param name = "pwd"> password </param> /// <Returns> </returns> Public static string SqlToClass (string SQL, string className, string server, string database, string uid, string pwd) { Using (SqlConnection conn = new SqlConnection (string. format ("server = {0}; uid = {2}; pwd = {3}; database = {1}", server, database, uid, pwd ))) { SqlCommand command = new SqlCommand (); Command. Connection = conn; Command. CommandText = SQL; DataTable dt = new DataTable (); SqlDataAdapter sad = new SqlDataAdapter (command ); Sad. Fill (dt ); Var reval = DataTableToClass (dt, className ); Return reval; } } /// <Summary> /// Obtain the object class String Based on the SQL statement /// </Summary> /// <Param name = "SQL"> SQL statement </param> /// <Param name = "className"> generated class name </param> /// <Param name = "connName"> connectionStrings name of webconfig </param> /// <Returns> </returns> Public static string SqlToClass (string SQL, string className, string connName) { String connstr = System. Configuration. ConfigurationManager. ConnectionStrings [connName]. ToString (); If (connstr. Contains ("metadata") // ef Connstr = Regex. Match (connstr, @ "connection string \ =" "(. +)" "). Groups [1]. Value; Using (SqlConnection conn = new SqlConnection (connstr )) { SqlCommand command = new SqlCommand (); Command. Connection = conn; Command. CommandText = SQL; DataTable dt = new DataTable (); SqlDataAdapter sad = new SqlDataAdapter (command ); Sad. Fill (dt ); Var reval = DataTableToClass (dt, className ); Return reval; } } /// <Summary> /// Matching type /// </Summary> /// <Param name = "type"> </param> /// <Returns> </returns> Private static string ChangeType (Type type) { String typeName = type. Name; Switch (typeName) { Case "Int32": typeName = "int"; break; Case "String": typeName = "string"; break; } Return typeName; } } }

The call is as follows:

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// Generate object classes using anonymous objects Var dynamicObj = new {id = 1, name = "", entity = new enityt1 ()}; // Note: only a single object cannot be passed into the List <T>, and the set must be List [0] String classCode = ClassGenerating. DynamicToClass (dynamicObj, "classDynamic ");     // Generate object classes through datatable DataTable dt = new DataTable (); Dt. Columns. Add ("Id", typeof (int )); Dt. Columns. Add ("Name ");   ClassCode = ClassGenerating. DataTableToClass (dt, "classTatabale ");     // Use SQL statements to generate entity classes ClassCode = ClassGenerating. SqlToClass ("select * from note", "Note", "127.0.0.1", "MyWork", "sa", "sasa "); ClassCode = ClassGenerating. SqlToClass ("select * from dbo. AccessoriesDetail", "AccessoriesDetail", "NFDEntities"); // use the config connstring name

Then, in the debugging status, CTRL + C the desired result and create a new class CTRL + V.