C #:D atatable map into model

This is a common problem in database development, of course, this can be solved with a ready-made ORM framework, but sometimes, if Dataset/datatable is returned by a third-party interface, ORM is inconvenient and has to be handled by itself.

Reflection of nature is essential, in addition, considering that the ColumnName in a DataTable is usually not strictly corresponding to the model's PropertyName, you can use attribute to record this mapping relationship.

Step 1: Create a Datafieldattribute class First

usingSystem;2  3 namespaceJimmy.orm4 { 5[AttributeUsage (attributetargets.property)]6      Public Sealed classDatafieldattribute:attribute7     { 8         /// <summary> 9         ///the field name corresponding to the tableTen         /// </summary> One          Public stringColumnName {Set;Get; } A  -          PublicDatafieldattribute (stringcolumnName) -         { theColumnName =ColumnName; -         } -     } -}

Step 2: on the class member of Model/entity, apply the DataField attribute, see the following code:

usingSystem;namespacejimmy.orm.entity{[Serializable] Public classproductentity:dataentitybase {[DataField ("Product_no")]         Public stringProductno {Set;Get; } [DataField ("product_id")]         Public intProductId {Set;Get; } [DataField ("Product_Name")]         Public stringProductName {Set;Get; }  Public Override stringToString () {return string. Format ("Productno:{1}{0}productid:{2}{0}productname:{3}", Environment.NewLine, Productno, ProductId, ProductName); }    }}

Step 3: The reflection came out, for the sake of convenience, encapsulated a Dataconvert class

usingSystem;usingSystem.Collections.Generic;usingSystem.Data;usingSystem.Reflection;namespacejimmy.orm{/// <summary>    ///convert datarow/datatable to entity/entity list/// </summary>     Public Static classDataconvert<t>whereT:dataentitybase,New()    {        /// <summary>        ///convert DataRow rows to entity/// </summary>        /// <param name= "Dr" ></param>        /// <returns></returns>         Public StaticT Toentity (DataRow DR) {T entity=NewT (); Type Info=typeof(T); varMembers =info.            GetMembers (); foreach(varMiinchMembers ) {                if(MI.) MemberType = =membertypes.property) {//the DataField attribute on the Read attribute                    Object[] attributes = mi. GetCustomAttributes (typeof(Datafieldattribute),true); foreach(varattrinchattributes) {                        varDatafieldattr = attr asDatafieldattribute; if(Datafieldattr! =NULL)                        {                            varPropinfo =info. GetProperty (mi.                            Name); if(Dr. Table.Columns.Contains (Datafieldattr.columnname)) {//Assign a relative field in DR to the entity property according to ColumnNamePropinfo.setvalue (Entity, Convert.cha Ngetype (Dr[datafieldattr.columnname], propinfo.propertytype),NULL); }                        }                    }                }            }            returnentity; }        /// <summary>        ///convert a DataTable into an entity list/// </summary>        /// <param name= "DT" ></param>        /// <returns></returns>         Public StaticList<t>ToList (DataTable dt) {List<T> list =NewList<t>(dt.            Rows.Count); foreach(DataRow Drinchdt. Rows) {list.            ADD (Toentity (DR)); }            returnlist; }    }}

Step 4: test

usingSystem;usingSystem.Data;usingJimmy.ORM.Entity;namespacejimmy.orm.test{classProgram {Static voidMain () {DataTable dt=NewDataTable (); Dt. Columns.Add ("Product_no"); Dt. Columns.Add ("product_id"); Dt. Columns.Add ("Product_Name"); Dt. Rows.Add ("00001",1,"Mobile Phone"); Dt. Rows.Add ("00002",2,"Apparel"); varProducts = dataconvert<productentity>.            ToList (DT); foreach(varEntityinchProducts )            {Console.WriteLine (entity);        } console.read (); }    }}

C #:D atatable map into model