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; }}
通过实例化参数，对属性赋值，将对象作为参数传入，反射获取对象名称，列名，列值。要求对象名与表名一致，属性与列名一致。
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以上就是mysql如何通过实例化对象参数查询数据 ？（源代码）的详细内容。