我有一个List<JobSeeker>
类型的列表。我想将它存储在ViewState中。如何做到这一点?
private List<JobSeeker> JobSeekersList { get; set; }
答案 0 :(得分:20)
基本上你只需要使用get
,然后就可以从视图状态获取发布的数据,或者在视图状态下第一次设置它。这是更强大的代码,可以避免对每个调用进行所有检查(视图状态设置,存在等),并直接保存并使用视图状态对象。
// using this const you avoid bugs in mispelling the correct key.
const string cJobSeekerNameConst = "JobSeeker_cnst";
public List<JobSeeker> JobSeekersList
{
get
{
// check if not exist to make new (normally before the post back)
// and at the same time check that you did not use the same viewstate for other object
if (!(ViewState[cJobSeekerNameConst] is List<JobSeeker>))
{
// need to fix the memory and added to viewstate
ViewState[cJobSeekerNameConst] = new List<JobSeeker>();
}
return (List<JobSeeker>)ViewState[cJobSeekerNameConst];
}
}
避免使用is
// using this const you avoid bugs in mispelling the correct key.
const string cJobSeekerNameConst = "JobSeeker_cnst";
public List<JobSeeker> JobSeekersList
{
get
{
// If not on the viewstate then add it
if (ViewState[cJobSeekerNameConst] == null)
ViewState[cJobSeekerNameConst] = new List<JobSeeker>();
// this code is not exist on release, but I check to be sure that I did not
// overwrite this viewstate with a different object.
Debug.Assert(ViewState[cJobSeekerNameConst] is List<JobSeeker>);
return (List<JobSeeker>)ViewState[cJobSeekerNameConst];
}
}
且JobSeeker
类必须为[Serializable]
[Serializable]
public class JobSeeker
{
public int ID;
...
}
并且您可以简单地将其称为对象,并且永远不会为null。也将在回发后返回保存在viewstate值上的
JobSeekersList.add(new JobSeeker(){ID=1});
var myID = JobSeekersList[0].ID;
答案 1 :(得分:2)
private IList<JobSeeker> JobSeekersList
{
get
{
// to do not break SRP it's better to move check logic out of the getter
return ViewState["key"] as List<JobSeeker>;
}
set
{
ViewState["key"] = value;
}
}