数据绑定 CheckBoxList 中的第一项未显示
假设我有一个名为“Facility”的 SQL 表，如下所示：
|| FacilityID || Name ||
0 Lecture Theatre
1 Seminar Room
2 Computer Lab
3 Electronics Lab
... ...
并针对 30 多个不同的房间设施继续这样。我正在尝试将这些数据绑定到 ASP.NET (C#) 中的 CheckBoxList，如下所示：
<asp:CheckBoxList ID="FacilityCheckList" AutoPostBack="true" runat="server">
</asp:CheckBoxList>
我用来在 C# 中实现此目的的代码如下所示：
String strSQL;
strSQL = "SELECT * FROM Facility";
SqlCommand cmd3 = new SqlCommand(strSQL, DBConnection);
DBConnection.Open();
SqlDataReader FacilityData;
FacilityData = cmd3.ExecuteReader();
FacilityData.Read();
FacilityCheckList.DataSource = FacilityData;
FacilityCheckList.DataValueField = "Name";
FacilityCheckList.DataBind();
DBConnection.Close();
现在这工作得很好，除了一件事：它不不显示列表中第一项“演讲厅”的复选框。列表中的所有其他设施都显示有一个复选框，但没有 - 我不知道为什么！
这在 SQL 方面不是问题，因为当我单独运行查询时，它会返回完整列表。我不认为它特定于 CheckBoxList，因为当我尝试绑定到 DropDownList 时，我遇到了同样的问题。我很困惑为什么要这样做，所以任何见解将不胜感激！
干杯
Suppose I have an SQL table entitled "Facility" which looks like this:
|| FacilityID || Name ||
0 Lecture Theatre
1 Seminar Room
2 Computer Lab
3 Electronics Lab
... ...
and continues as such for 30-odd different room facilities. I'm trying to Databind these to a CheckBoxList in ASP.NET (C#) which looks like this:
<asp:CheckBoxList ID="FacilityCheckList" AutoPostBack="true" runat="server">
</asp:CheckBoxList>
The code I'm using to achieve this in C# looks like this:
String strSQL;
strSQL = "SELECT * FROM Facility";
SqlCommand cmd3 = new SqlCommand(strSQL, DBConnection);
DBConnection.Open();
SqlDataReader FacilityData;
FacilityData = cmd3.ExecuteReader();
FacilityData.Read();
FacilityCheckList.DataSource = FacilityData;
FacilityCheckList.DataValueField = "Name";
FacilityCheckList.DataBind();
DBConnection.Close();
Now this works absolutely fine, apart from one thing: it doesn't display a CheckBox for the first item in the list, Lecture Theatre. Every other facility in the list shows up with a CheckBox just fine, but not Lecture Theatre - and I have no idea why!
It's not a problem on the SQL side cos when I run the query on its own, it returns the full list. And I don't think it's specific to CheckBoxList, because when I tried binding to a DropDownList instead, I got the same problem. I'm pretty much stumped as to why it is doing this, so any insight would be much appreciated!
Cheers
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删除该行：
这会导致阅读器向前移动一个档次，从而使您丢失第一个项目
Remove the line:
This is causing the reader to move forward one notch making you lose the first item
不要在
SqlReader上调用Read()。只需在调用 ExecuteReader() 后将其指定为 CheckBoxList 的数据源即可。当您将其设置为数据源时，它首先调用 Read()，因此在您的情况下，第一条记录将被跳过。
Don't call
Read()onSqlReader. Just assign it as a datasource for your CheckBoxList after callingExecuteReader().When you set it as a DataSource, it starts by calling Read(), and thus in your case the first record gets skipped.