public class Test
{
public void MyObj<T>() where T : class
{
//T t = new T();
T t =System.Activator.CreateInstance<T>();
//获取类型跟字段然后拿到对应名字方法跟字段就可以了
}
}
微信官方创建实体的方法,通过泛型类型创建实例
System.Activator.CreateInstance<T>();
新增：
public static void Add<T>(T model)
{
Type t = typeof(T);
string TableName = GetTableName(t);
PropertyInfo[] pps = t.GetProperties();
StringBuilder sb = new StringBuilder("insert into"+ TableName + "(");
StringBuilder sbColumns = new StringBuilder();
StringBuilder sbValues = new StringBuilder();
foreach (PropertyInfo item in pps)
{
if (!IsNotMapper(item)&& !IsKey(item))
{
sbColumns.Append(item.Name+",");
if (IsNoStr(item.PropertyType))
{
if (item.GetValue(model)==null|| string.IsNullOrEmpty(item.GetValue(model).ToString()))
{
sbValues.Append("null,");
}
else
{
if (IsBoolean(item.PropertyType))
{
bool bvalue = (bool)item.GetValue(model);
sbValues.Append((bvalue?1:0) + ",");
}
else
{
sbValues.Append(item.GetValue(model) + ",");
}
}
}
else
{
sbValues.Append("'"+item.GetValue(model) + "',");
}
}
}
string sql = string.Format("insert into " + TableName + "({0}) values({1})",sbColumns.ToString().TrimEnd(','), sbValues.ToString().TrimEnd(','));
connection.Execute(sql);
}
修改：
public static void Update<T>(T model)
{
Type t = typeof(T);
string TableName = GetTableName(t);
PropertyInfo[] pps = t.GetProperties();
StringBuilder sb = new StringBuilder();
string where = "";
foreach (PropertyInfo item in pps)
{
if (!IsNotMapper(item))
{
string column = item.Name;
string value = item.GetValue(model).ToString();
if (!IsKey(item))
{
if (IsNoStr(item.PropertyType))
{
if (IsBoolean(item.PropertyType))
{
bool bvalue = (bool)item.GetValue(model);
value = bvalue ? "1" : "0";
}
sb.Append(column + "=" + value + ",");
}
else
{
sb.Append(column + "='" + value + "',");
}
}
else
{
where = column + "=" + value;
}
}
}
string sql = string.Format("update {0} set {1} where {2} ",TableName,sb.ToString().TrimEnd(','),where);
}
删除：
public static void Delete<Key, T>(Key id)
{
Type tp = typeof(T);
PropertyInfo[] pps = tp.GetProperties();
string KeyName = "";
Key Value = id;
foreach (PropertyInfo item in pps)
{
if (!IsNotMapper(item)&& IsKey(item))
{
KeyName = item.Name;
}
}
if (IsNoStr(typeof(Key)))
{
string sql = "delete " + GetTableName(tp) + " where " + KeyName + "=" + Value;
}
else
{
string sql = "delete " + GetTableName(tp) + " where " + KeyName + "='" + Value + "'";
}
}
判断字段或类是否包含特性：
/// <summary>
/// 是否包含该特性
/// </summary>
/// <param name="item"></param>
/// <param name="tp"></param>
/// <returns></returns>
private static bool IsAttribute(PropertyInfo item, Type tp)
{
var attr = item.GetCustomAttributes(tp, true);
if (attr.Length <= 0)
return false;
return true;
}
抓取指定特性值（如表名，子段说明等特殊的属性）：
/// <summary>
/// 查询表名
/// </summary>
/// <param name="t"></param>
/// <returns></returns>
private static string GetTableName(Type t)
{
string Name = t.Name;
object[] os = t.GetCustomAttributes(typeof(TablNameAttribute), true);
if (os.Length > 0)
{
TablNameAttribute ta = os[0] as TablNameAttribute;
Name = ta.TableName;
}
return Name;
}
泛型反射是我们在做系统架构时需要经常用到的，如果能熟练应用到项目中可以对业务开发起到约束和管控的作用。