Using expression tree + reflection to implement simple ORM object mapping operation

using expression tree + reflection to implement simple ORM object mapping operation

For the sake of simplicity I create a file BaseDAL.cs, the use of the method is also very simple, look at the code first to create a model

Using System;
Using System.Collections.Generic;
Using System.Linq;
Using System.Text;

Namespace Basedal.model
{
    [Table ("UserInfo")] public
    class Mduserinfo
    {
        ///<summary>
        ///User number
        ///</summary>
        /// 
        [PrimaryKey] public
        string Userno {set; get;}

        <summary>
        ///Store number
        ///</summary> public
        string Shopno {set; get;}

        <summary>
        ///user name
        ///</summary> public
        string USERNAMC {set; get;}
    }

then after creating a Userinfodal class inherits from Basedal

Using System;
Using System.Collections.Generic;
Using System.Linq;
Using System.Text;
Using Basedal.model;

Namespace Basedal.dal
{public
    class userinfodal:basedal<mduserinfo>
    {

    }
}

Okay, so here's how to use the example.

Using Basedal.dal;
Using Basedal.model;
Using System;
Using System.Collections.Generic;
Using System.Linq;
Using System.Text;

Using System.Threading.Tasks; Namespace Basedal {class Program {static void Main (string[] args) {Userinfodal user
            Infodal = new Userinfodal (); Check list<mduserinfo> listuser = Userinfodal.query (P => p.usernamc.contains ("horse") && P.userno =

            = "00008"); change for (int i = 0; i < Listuser.count i++) {listuser[i]. USERNAMC = Listuser[i].
                USERNAMC + i;
            Userinfodal.update (Listuser[i]);
            }//Add mduserinfo UserInfo = new Mduserinfo ();
            Userinfo.userno = "00001";
            USERINFO.USERNAMC = "Test new";
            Userinfo.shopno = "10"; 

            Userinfodal.insert (UserInfo);

        Delete Userinfodal.delete (p => p.userno = = "00001"); }
    }
}

The main idea of the

is to use the expression expression tree + reflection, and is to use attribute to annotate the class, simple 400 lines of code ٩ (๑❛ᴗ❛๑) ۶ BaseDAL.cs code

Using System;
Using System.Collections.Generic;
Using System.Linq;
Using System.Text;
Using System.Linq.Expressions;
Using System.Data.SqlClient;
Using System.Data;

Using System.Reflection; namespace Basedal {///<summary>///Data base Access class///</summary>///<typeparam name= "tentity" &
        Gt;</typeparam> public class basedal<tentity> where Tentity:class {///<summary> Database connection string///</summary> public static string SqlConnection = "Server=192.168.1.12;database=e

        atpos2;uid=sa;pwd=1234; "; 
        <summary>///Current Action table name///</summary> public string tablename {get; private set;}  <summary>///table column///</summary> private datacolumncollection Tablecolumns

        {set;get;} <summary>///Model Properties list///</summary> private list<propertyinfo> Listproper ty = new LIST&LT;PROpertyinfo> ();  <summary>///Current table primary key///</summary> private list<propertyinfo> Listprimarykey

        = new List<propertyinfo> ();

        <summary>///Callout Self-Adding column attribute///</summary> private PropertyInfo autoincrease = null;
            Public Basedal () {Type type = typeof (Tentity); #region Initialize table name object[] Objs = type.
            GetCustomAttributes (typeof (Tableattribute), false); if (OBJS.
                Length > 0) {tableattribute table = objs[0] as Tableattribute; TableName = table.
            TableName; else {tablename = type.
            Name; #endregion #region Initialize the property list propertyinfo[] Propertys = type.
            GetProperties ();
            ListProperty = new list<propertyinfo> (propertys); foreach (PropertyInfo property in ListProperty)
            {Attribute Primary = property.
               GetCustomAttribute (typeof (Primarykeyattribute));
               if (primary!=null) {Listprimarykey.add (property); Attribute Autoincrease = property.
               GetCustomAttribute (typeof (Autoincreaseattribute));
               if (autoincrease!= null) {Autoincrease = property; 
        } #endregion}///<summary>///query///</summary> <param name= "expression" ></param>///<returns></returns> public List <TEntity> Query (expression<func<tentity, bool>> Expression = null) {StringBuilder b
            Uff = new StringBuilder (); if (expression!= null) {expressionhelper.parseexpression (expression).
            body, buff); } String strSQL =String.
            Format ("select * from {0}", tablename); if (buff. Length > 0) {strSQL = "Where" +buff.
            ToString ();
            } list<tentity> listentity = new list<tentity> ();
            DataTable table = sqlhelper.executetable (strSQL); Tablecolumns = table.
            Columns; foreach (DataRow DataRow in table).
                Rows) {tentity model = datarowtoentity (DataRow);
            Listentity.add (model);
        return listentity; ///<summary>///update///</summary>///<param name= "model" ></para m>///<returns></returns> public int Update (tentity model) {#region structure
            Build Set field StringBuilder Setbuff = new StringBuilder ();
       foreach (PropertyInfo property in ListProperty) {if (listprimarykey.contains)             Continue if (Setbuff. Length > 0) {setbuff.
                Append (","); } Object value = property.
                GetValue (model); Setbuff. AppendFormat ("{0}={1}", property.)
            Name, Expressionhelper.getsqlvalue (value));
            #endregion #region build where field string Strwhere= "";
                if (Listprimarykey.count > 0) {foreach (PropertyInfo property in Listprimarykey)
                    {if (strwhere!= "") {strwhere + = "and"; } Object value = property.
                    GetValue (model); strwhere = = String. Format (' {0}={1} ', property.
                Name, Expressionhelper.getsqlvalue (value));
            } strwhere = "Where" + strwhere; #endregion string strSQL = string. Format ("Update {0} Set {1} {2} ", Tablename,setbuff.
            ToString (), strwhere);
        Return Sqlhelper.executesql (strSQL); ///<summary>///Add///</summary>///<param name= "model" ></para m>///<returns></returns> public int Insert (tentity model) {Stringbui
            Lder fieldName = new StringBuilder ();
            StringBuilder fieldvalue = new StringBuilder (); foreach (PropertyInfo listproperty) {if autoincrease!= null && property .
                Equals (autoincrease)) continue;
                    if (Fieldname.length > 0) {fieldname.append (",");
                Fieldvalue.append (","); } fieldname.append (property.
                Name); Fieldvalue.append (Expressionhelper.getsqlvalue.
            GetValue (model)); String strSQL = String. FOrmat ("Insert into {0} ({1}) Values ({2})", Tablename,fieldname.tostring (), fieldvalue.tostring ());
                if (autoincrease!= null) {strSQL + = "\r\n;select @ @IDENTITY";
                Object obj = Sqlhelper.executescalar (strSQL);
                Autoincrease.setvalue (model, obj);
            return Convert.ToInt32 (obj);
        Return Sqlhelper.executesql (strSQL); }///<summary>///delete///</summary>///<param name= "expression" >< /param>///<returns></returns> public int Delete (expression<func<tentity, BOOL&GT;&G T
            expression) {StringBuilder buff = new StringBuilder (); if (expression!= null) {expressionhelper.parseexpression (expression).
            body, buff); String strSQL = String.
            Format ("Delete from {0}", tablename); if (buff.
 Length > 0)           {strSQL = "Where" + buff.
            ToString ();
        Return Sqlhelper.executesql (strSQL); #region Private Method///<summary>///converted to model///</summary>///&LT;PA Ram Name= "DataRow" ></param>///<returns></returns> private tentity datarowtoentity (D Atarow dataRow) {ConstructorInfo construct = typeof (Tentity).
           GetConstructor (New type[]{}); Object model = construct.
           Invoke (NULL);
               for (int i = 0; i < Listproperty.count i++) {PropertyInfo property = Listproperty[i]; If (property, Tablecolumns.contains. Name)) {property. SetValue (model, Datarow[property.
               Name], NULL);
        } return model as tentity; #endregion} #region expressionhelper + expression help class///<summary>///expression HelpClass///</summary> class Expressionhelper {///<summary>///parsing where condition/// </summary>///<param name= "expression" ></param>///<param name= "Buff" ></param > public static void ParseExpression (Expression Expression, StringBuilder buff) {Binaryexp
            Ression binary = null;
            Memberexpression left = null;
            ConstantExpression rigth = null; if (expression. NodeType = = expressiontype.andalso) {parseexpression (expression as system.linq.expressions.b inaryexpression).
                Left, buff); Buff.
                Append ("and"); ParseExpression ((expression as System.Linq.Expressions.BinaryExpression).
            right, buff); else if (expression. NodeType = = Expressiontype.orelse) {parseexpression (expression as System.Linq.Expressions.Bi naryexpression).
       Left, buff);         Buff.
                Append ("Or"); ParseExpression ((expression as System.Linq.Expressions.BinaryExpression).
            right, buff); else if (expression. NodeType = = Expressiontype.call) {Methodcallexpression call = expression as Methodcallexpress
                Ion String methodname = call.
                Method.name; if (methodname = = "Contains") {left = call.
                    Object as Memberexpression; Rigth = call.
                    Arguments[0] as ConstantExpression; Buff. AppendFormat ("{0} like '%{1}% '", left. Member.name, Rigth.
                Value); } else {binary = expression as System.Linq.Expressions.BinaryExpres
                Sion left = binary.
                Left as Memberexpression; rigth = binary.
                Right as ConstantExpression; switch (expression. NodeType) {Case ExpressiOnType.Equal:buff. AppendFormat (' {0} = {1} ', left. Member.name, Getsqlvalue (rigth.
                        Value));
                    Break Case ExpressionType.NotEqual:buff. AppendFormat ("{0} <> {1}", left. Member.name, Getsqlvalue (rigth.
                        Value));
                    Break Case expressiontype.greaterthan://is larger than buff. AppendFormat ("{0} > {1}", left. Member.name, Getsqlvalue (rigth.
                        Value));
                    Break Case expressiontype.greaterthanorequal://is greater than or equal to buff. AppendFormat ("{0} >= {1}", left.) Member.name, Getsqlvalue (rigth.
                        Value));
                    Break Case expressiontype.lessthan://is less than buff. AppendFormat ("{0} < {1}", left. Member.name, Getsqlvalue (rigth.
                        Value));
                    Break
                    Case expressiontype.lessthanorequal://less than or equal    Buff. AppendFormat ("{0} <= {1}", left.) Member.name, Getsqlvalue (rigth.
                        Value));

                Break
        } return; ///<summary>///Fetch SQL parameter value///</summary>///<param name= "obj" ></p
            aram>///<returns></returns> public static string Getsqlvalue (Object obj) {
            if (obj = null) return ""; if (obj. GetType (). Equals (typeof (String)) {return string. Format ("' {0} '", obj.)
            ToString ()); else if (obj. GetType (). Equals (typeof (DateTime)) {return string. Format ("' {0} '"), Convert.todatetime (obj).
            ToString ("Yyyy-mm-dd HH:mm:ss")); else if (obj. GetType (). Equals (typeof (int)) | | Obj. GetType (). Equals