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 ?(源代码),有一定的参考价值,有需要的朋友可以参考一下,希望对你有所帮助。 public static string Query
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 ?(源代码),有一定的参考价值,有需要的朋友可以参考一下,希望对你有所帮助。
public static string QueryByEntity<T>(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<T>(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<T> tList = new List<T>(); 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("查询数据库失败,{0}", ex.Message));
} finally
{ if (reader != null)
{
reader.Close();
reader.Dispose();
}
} return resultstr;
}internal static class ObjectExtend
{ public static object GetPropertyValue<T>(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;
}
}
--结束END--
本文标题: MySQL通过实例化对象参数查询实例讲解
本文链接: https://www.lsjlt.com/news/52670.html(转载时请注明来源链接)
有问题或投稿请发送至: 邮箱/279061341@qq.com QQ/279061341
下载Word文档到电脑,方便收藏和打印~
2024-04-29
2024-04-29
2024-04-29
2024-04-29
2024-04-28
2024-04-28
2024-04-28
2024-04-28
2024-04-28
2024-04-28
回答
回答
回答
回答
回答
回答
回答
回答
回答
回答
0