MySQL通過(guò)實(shí)例化對(duì)象參數(shù)如何查詢數(shù)據(jù)

下文主要給大家?guī)?lái)MySQL通過(guò)實(shí)例化對(duì)象參數(shù)如何查詢數(shù)據(jù) ，希望這些內(nèi)容能夠帶給大家實(shí)際用處，這也是我編輯MySQL通過(guò)實(shí)例化對(duì)象參數(shù)如何查詢數(shù)據(jù) 這篇文章的主要目的。好了，廢話不多說(shuō)，大家直接看下文吧。                                                          

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("查詢數(shù)據(jù)庫(kù)失敗，{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;
    }
}

通過(guò)實(shí)例化參數(shù)，對(duì)屬性賦值，將對(duì)象作為參數(shù)傳入，反射獲取對(duì)象名稱，列名，列值。要求對(duì)象名與表名一致，屬性與列名一致。

對(duì)于以上關(guān)于MySQL通過(guò)實(shí)例化對(duì)象參數(shù)如何查詢數(shù)據(jù) ，大家是不是覺(jué)得非常有幫助。如果需要了解更多內(nèi)容，請(qǐng)繼續(xù)關(guān)注我們的行業(yè)資訊，相信你會(huì)喜歡上這些內(nèi)容的。