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我創建了一個顯示錶格的網頁。表中的大部分單元格都已填充，但其中一些單元需要用戶輸入。我想在這些表格單元格中放置下拉菜單，這樣單元格將填充選擇菜單，下拉列表將消失。Visual Web Developer在桌子單元格中放置Drowdown菜單
我已經得到了這個在單個單元格中工作。但是，當我試圖讓它在第二個單元中工作時，一切都破裂了。我曾試圖發現這個問題，我甚至不確定我是否記得現在第一個人的工作。 :-)
下面是相關代碼：
protected void Page_Load(object sender, EventArgs e)
{
// Create a DropDownList control.
DropDownList DropList = new DropDownList();
// Set the properties for the DropDownList control.
DropList.ID = "TrendList";
DropList.AutoPostBack = true;
// Manually register the event-handling method for the
// SelectedIndexChanged event.
DropList.SelectedIndexChanged += new EventHandler(this.Selection_Change);
// Because the DropDownList control is created dynamically each
// time the page is loaded, the data must be bound to the
// control each time the page is refreshed.
// Specify the data source and field names for the Text and
// Value properties of the items (ListItem objects) in the
// DropDownList control.
DropList.DataSource = CreateDataSource();
DropList.DataTextField = "ColorTextField";
DropList.DataValueField = "ColorValueField";
// Bind the data to the control.
DropList.DataBind();
// Set the default selected item when the page is first loaded.
if (!IsPostBack)
{
DropList.SelectedIndex = 0;
}
// Add the DropDownList control to the Controls collection of
// the PlaceHolder control.
p1.Controls.Add(DropList);
p2.Controls.Add(DropList);
}
ICollection CreateDataSource()
{
// Create a table to store data for the DropDownList control.
DataTable dt = new DataTable();
// Define the columns of the table.
dt.Columns.Add(new DataColumn("ColorTextField", typeof(String)));
dt.Columns.Add(new DataColumn("ColorValueField", typeof(String)));
// Populate the table with sample values.
dt.Rows.Add(CreateRow("GreenUp", "GreenUp", dt));
dt.Rows.Add(CreateRow("GreenFlat", "GreenFlat", dt));
dt.Rows.Add(CreateRow("GreenDown", "GreenDown", dt));
dt.Rows.Add(CreateRow("YellowUp", "YellowUp", dt));
dt.Rows.Add(CreateRow("YellowFlat", "YellowFlat", dt));
dt.Rows.Add(CreateRow("YellowDown", "YellowDown", dt));
dt.Rows.Add(CreateRow("RedUp", "RedUp", dt));
dt.Rows.Add(CreateRow("RedFlat", "RedFlat", dt));
dt.Rows.Add(CreateRow("RedDown", "RedDown", dt));
dt.Rows.Add(CreateRow("ClearUp", "ClearUp", dt));
dt.Rows.Add(CreateRow("ClearFlat", "ClearFlat", dt));
dt.Rows.Add(CreateRow("ClearDown", "ClearDown", dt));
// Create a DataView from the DataTable to act as the data source
// for the DropDownList control.
DataView dv = new DataView(dt);
return dv;
}
DataRow CreateRow(String Text, String Value, DataTable dt)
{
// Create a DataRow using the DataTable defined in the
// CreateDataSource method.
DataRow dr = dt.NewRow();
// This DataRow contains the ColorTextField and ColorValueField
// fields, as defined in the CreateDataSource method. Set the
// fields with the appropriate value. Remember that column 0
// is defined as ColorTextField, and column 1 is defined as
// ColorValueField.
dr[0] = Text;
dr[1] = Value;
return dr;
}
void Selection_Change(Object sender, EventArgs e)
{
// Retrieve the DropDownList control from the Controls
// collection of the PlaceHolder control.
DropDownList DropList1 = (DropDownList)p1.FindControl("TrendList");
DropDownList DropList2 = (DropDownList)p2.FindControl("TrendList");
switch (sender.ToString())
{
case "p1":
s1.InnerHtml = DropList1.SelectedItem.Value;
break;
case "p2":
s2.InnerHtml = DropList2.SelectedItem.Value;
break;
}
}
，這裏是從表中的相關片段：
<td><span id="s1" runat="server"><asp:PlaceHolder ID="p1" runat="server"></asp:PlaceHolder></span>
<td><span id="s2" runat="server"><asp:PlaceHolder ID="p2" runat="server"></asp:PlaceHolder></span>
現在我認識到開關控制是完全錯誤的，因爲發送者不代表來電者的身份。但我需要一些方法來區分哪個下拉菜單是調用者，所以我知道要替換哪個HTML。另外，我一次只能顯示一個下拉菜單。
任何意見表示讚賞。
問候。