仅使用该代码片段且没有错误消息，它几乎不可能分辨，但很可能你使用的是错误的DataAdapter。

尝试：

With just that code fragment and no error message, it's pretty much impossible to tell, but it's likely that you are using the wrong DataAdapter.
Try:

SqlDataAdapter da = new SqlDataAdapter(q,constr);
DataTable dt = new DataTable();
da.Fill(dt);
GridView1.DataSource = dt;
GridView1.DataBind();

如果这不起作用，我们需要错误信息及其抱怨的行。

And if that doesn't work, we would need the error message, and the line it is complaining about.