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The content of this article is about how MySQL queries data by instantiating object parameters. (source code), there is a certain reference value, friends in need can refer to, hope to help you.

Public static string QueryByEntity (T t) where T: new () {string resultstr = string.Empty; MySqlDataReader reader = null; try {Type type = typeof (T); PropertyInfo [] properties = type.GetProperties (); string select = string.Format ("Select * from {0} {1}", type.Name, "{0}"); string where = string.Empty; foreach (PropertyInfo property in properties) {var value = t.GetPropertyValue (property) If (value! = null & &! value.Equals (property.GetDefaultValue () {if (string.IsNullOrEmpty (where)) {where = string.Format ("where {0} ='{1}'", property.Name, value);} else {where = string.Format ("{0} and {1} ='{2}'", where, property.Name, value) } select = string.Format (select, where); MySqlConnection connection = OpenConnection (); if (connection = = null) return resultstr; MySqlCommand _ sqlCom = new MySqlCommand (select, connection); reader = _ sqlCom.ExecuteReader (); List tList = new List (); while (reader.Read ()) {T T1 = new T () Foreach (PropertyInfo property in properties) {if (! string.IsNullOrEmpty (Reader [property.Name]. ToString ()) {property.SetMethod.Invoke (T1, new object [] {reader [property.Name]});}} tList.Add (T1);} resultstr = JsonConvert.SerializeObject (tList) } catch (Exception ex) {Logging.Error (string.Format ("query database failed, {0}", ex.Message));} finally {if (reader! = null) {reader.Close (); reader.Dispose ();}} return resultstr;} internal static class ObjectExtend {public static object GetPropertyValue (this object obj, PropertyInfo property) {Type type = typeof (T); PropertyInfo propertyInfo = type.GetProperty (property.Name) If (propertyInfo! = null) {return propertyInfo.GetMethod.Invoke (obj, null);} return null;} public static object GetDefaultValue (this PropertyInfo property) {return property.PropertyType.IsValueType? Activator.CreateInstance (property.PropertyType): null;}}

By instantiating the parameter, assigning a value to the property, passing the object as a parameter, and reflecting to get the object name, column name, column value. The object name is required to be consistent with the table name, and the attribute is consistent with the column name. Thank you for your support.

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