store表达式>作为一个类属性
本文关键字:一个 属性 Func 表达式 store boolean | 更新日期: 2023-09-27 18:16:43
我有一个类扩展了System.Web.UI.WebControls.GridView控件。我想有一个属性,可以保存我的EF表达式在整个控件中使用。
问题是T没有定义
public sealed class NCGridView : GridView
{
private Expression<Func<T, bool>> _where;
public void LoadWhere(Expression<Func<T, bool>> where)
{
_where = where;
}
}
RedHat建议尝试
private Expression<Func<BaseModel, bool>> _where;
public void LoadWhere<T>(Expression<Func<T, bool>> where) where T : BaseModel
{
// Cannot cast from: Expression<Func<T, bool>> to: Expression<Func<BaseModel, bool>>
_where = where;
}
答案二:更新:
public Expression<Func<BaseModel, bool>> LoadWhere<T>(Expression<Func<T, bool>> where) where T : BaseModel
{
where = LambdaExpression.Lambda<Func<BaseModel, bool>>(where.Body,where.Parameters);
}
答案1:用途:
Expression<Func<object, bool>>
支持任意类型
示例:Expression<Func<object, bool>> exp = p => ((Table1)p).Code == 1;
var a = new MyContext().Table1.Where(exp).ToList();