我得到了一些 c# 代码,并被要求创建一个与之配套的标记 (.aspx) 文件。
我不是在寻求帮助来编写代码,而是在寻求如何去做。
这是代码:
public partial class search : Page
{
protected override void OnLoad(EventArgs e)
{
int defaultCategory;
try
{
defaultCategory = Int32.Parse(Request.QueryString["CategoryId"]);
}
catch (Exception ex)
{
defaultCategory = -1;
}
Results.DataSource = GetResults(defaultCategory);
Results.DataBind();
if (!Page.IsPostBack)
{
CategoryList.DataSource = GetCategories();
CategoryList.DataTextField = "Name";
CategoryList.DataValueField = "Id";
CategoryList.DataBind();
CategoryList.Items.Insert(0, new ListItem("All", "-1"));
CategoryList.SelectedIndex = CategoryList.Items.IndexOf(CategoryList.Items.FindByValue(defaultCategory.ToString()));
base.OnLoad(e);
}
}
private void Search_Click(object sender, EventArgs e)
{
Results.DataSource = GetResults(Convert.ToInt32(CategoryList.SelectedValue));
Results.DataBind();
}
private DataTable GetCategories()
{
if (Cache["AllCategories"] != null)
{
return (DataTable) Cache["AllCategories"];
}
SqlConnection connection = new SqlConnection("Data Source=DB;Initial Catalog=Store;User Id=User;Password=PW;");
string sql = string.Format("SELECT * From Categories");
SqlCommand command = new SqlCommand(sql, connection);
SqlDataAdapter da = new SqlDataAdapter(command);
DataTable dt = new DataTable();
da.Fill(dt);
Cache.Insert("AllCategories", dt, null, DateTime.Now.AddHours(1), System.Web.Caching.Cache.NoSlidingExpiration);
connection.Dispose();
return dt;
}
private DataTable GetResults(int categoryId)
{
SqlConnection connection = new SqlConnection("Data Source=DB;Initial Catalog=Store;User Id=User;Password=PW;");
string sql = string.Format("SELECT * FROM Products P INNER JOIN Categories C on P.CategoryId = C.Id WHERE C.Id = {0} OR {0} = -1", categoryId);
SqlCommand command = new SqlCommand(sql, connection);
SqlDataAdapter da = new SqlDataAdapter(command);
DataTable dt = new DataTable();
da.Fill(dt);
connection.Dispose();
return dt;
}
}
编辑
在上面的代码中,Results 对象是什么,CategoryList 只是一个列表框吗?