MySQL数据库实例化参数优化与实例查询详解

本篇文章给大家带来的内容是关于MySQL如何通过实例化对象参数查询数据 &＃xff1f;(源代码)&＃xff0c;有一定的参考价值&＃xff0c;有需要的朋友可以参考一下&＃xff0c;希望对你有所帮助。

public static string QueryByEntity(T t) where T : new()

{ string resultstr &＃61; string.Empty;

MySqlDataReader reader &＃61; null; try

{

Type type &＃61; typeof(T);

PropertyInfo[] properties &＃61; type.GetProperties(); string select &＃61; string.Format("Select * from {0} {1}", type.Name, "{0}"); string where &＃61; string.Empty; foreach (PropertyInfo property in properties)

{ var value &＃61; t.GetPropertyValue(property); if (value !&＃61; null && !value.Equals(property.GetDefaultValue()))

{ if (string.IsNullOrEmpty(where))

{ where &＃61; string.Format(" where {0}&＃61;&＃39;{1}&＃39; ", property.Name, value);

} else

{ where &＃61; string.Format(" {0} and {1} &＃61; &＃39;{2}&＃39; ", where, property.Name, value);

}

}

} select &＃61; string.Format(select, where);

MySqlConnection connection &＃61; OpenConnection(); if (connection &＃61;&＃61; null) return resultstr;

MySqlCommand _sqlCom &＃61; new MySqlCommand(select, connection);

reader &＃61; _sqlCom.ExecuteReader();

List tList &＃61; new List(); while (reader.Read())

{

T t1 &＃61; 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 &＃61; JsonConvert.SerializeObject(tList);

} catch (Exception ex)

{

Logging.Error(string.Format("查询数据库失败&＃xff0c;{0}", ex.Message));

} finally

{ if (reader !&＃61; null)

{

reader.Close();

reader.Dispose();

}

} return resultstr;

}internal static class ObjectExtend

{ public static object GetPropertyValue(this object obj, PropertyInfo property)

{

Type type &＃61; typeof(T);

PropertyInfo propertyInfo &＃61; type.GetProperty(property.Name); if (propertyInfo !&＃61; 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;

}

}

通过实例化参数&＃xff0c;对属性赋值&＃xff0c;将对象作为参数传入&＃xff0c;反射获取对象名称&＃xff0c;列名&＃xff0c;列值。要求对象名与表名一致&＃xff0c;属性与列名一致&＃xff0c;感谢大家对我们的支持。

本文标题: MySQL通过实例化对象参数查询实例讲解

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