你调用的对象是空的。 -c＃-中继器-数据集

Question

Hi there, the above image shows the exception i'm getting everytime I filter the DataTable generated from the object I created.

dtHistory = cBLRead.ds2.Tables["ScheduleHistory"]; --> This actually populates the dtHistory.

dtHistory.DefaultView.RowFilter = string.Format("[ExamScheduleID] in({0})", hdnID) --> This line filters the rows based on the hdnID...

rptHistory is already created in my ASP client side and it will remain empty not until the user clicks a specific row located in another DataTable...

I pinned the dtHistory.Rows.Count to show that dtHistory is not null

How will I solve this one?

---Here's what I want to happen---

Everytime the user clicks a specific row of Examination from DataTable, a modal which contains a Repeater that shows the Reschedule History of Examination will pop-up.

The modal works ok but the repeater I have made does not. What is probably the main cause of this exception..

Any reply will be appreciated. Thanks!

Answer 1

The exception does not mean that dtHistory is null but that rptHistory is null . Then as you are trying to dereference it to access the DataSource property it throws.

In the screenshot the ScheduleHistory method seems suspicious:

ClaretExamSchedule callMethod = new ClaretExamSchedule();
callMethod.FilterHistory(hdnId);

You instantiate a new object and call the FilterHistory method which throws the exception because presumably the rptHistory member is still unitialized.

Answer 2

您应该像这样分配数据源

rptHistory.DataSource=dtHistory.Tables[0];