我有一個基于資料庫動態創建的gridview。gridview 的某些行有 2 個 DropDownLists，而其他行不依賴于行中的專案。該行的第二個 DropDownList 是根據第一個 DrowpDownMenu 的選擇動態創建的。一切正常，除了，如果您在第一行進行選擇，然后更改第二行的第一個 DropDownList 的選擇或單擊更新按鈕，它將重置第一行的第二個 DropDownList。這顯然是由于 PostBack。但我想保持選擇，直到所有 DropDownLists 都被選中并將更改保存到資料庫中。任何幫助將不勝感激。
我的網格視圖：
<asp:GridView ID="CartList" runat="server" AutoGenerateColumns="False" ShowFooter="True"
GridLines="Vertical" CellPadding="4" CssClass="table table-striped table-bordered"
OnRowDataBound="CartList_RowDataBound">
<Columns>
<asp:BoundField DataField="ProductID" HeaderText="ID" SortExpression="ProductID" />
<asp:BoundField DataField="Product.ProductName" HeaderText="Name" />
<asp:BoundField DataField="Product.UnitPrice" HeaderText="Price (each)" DataFormatString="{0:c}" />
<asp:TemplateField HeaderText="Quantity">
<ItemTemplate>
<asp:TextBox ID="PurchaseQuantity" Width="40" runat="server" Text='<%# Eval("Quantity") %>'></asp:TextBox>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Size">
<ItemTemplate>
<asp:DropDownList ID="Sizeddl" runat="server" Font-Size="Medium"
AutoPostBack="true" ForeColor="Black" OnSelectedIndexChanged="Sizeddl_SelectedIndexChanged">
</asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Color">
<ItemTemplate>
<asp:DropDownList ID="ColorNameddl" runat="server"
Font-Size="Medium" ForeColor="Black">
</asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Item Total">
<ItemTemplate>
<%#: String.Format("{0:c}", ((Convert.ToDouble( Eval("Quantity") )) * Convert.ToDouble(Eval("Product.UnitPrice"))))%>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Remove Item">
<ItemTemplate>
<asp:CheckBox ID="Remove" runat="server"></asp:CheckBox>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
<div>
<p></p>
<strong>
<asp:Label ID="LabelSubtotal" runat="server" Text="SubTotal: "></asp:Label>
<asp:Label ID="lblSubtotal" runat="server" EnableViewState="false"></asp:Label>
</strong>
<p></p>
<strong>
<asp:Label ID="LabelTax" runat="server" Text="Tax Total: "></asp:Label>
<asp:Label ID="lblTax" runat="server" EnableViewState="false"></asp:Label>
</strong>
<p></p>
<strong>
<asp:Label ID="LabelTotalText" runat="server" Text="Order Total: "></asp:Label>
<asp:Label ID="lblTotal" runat="server" EnableViewState="false"></asp:Label>
</strong>
</div>
<br />
<table>
網格視圖加載：
DataTable rstSize = new DataTable();
protected void Page_Load(object sender, EventArgs e)
{
using (ShoppingCartActions usersShoppingCart = new ShoppingCartActions())
{
decimal cartTotal = 0;
cartTotal = usersShoppingCart.GetTotal();
if (cartTotal > 0)
{
// Display Total.
lblSubtotal.Text = String.Format("{0:c}", usersShoppingCart.GetSubtotal());
lblTax.Text = String.Format("{0:c}", usersShoppingCart.GetTax());
lblTotal.Text = String.Format("{0:c}", usersShoppingCart.GetTotal());
}
else
{
lblSubtotal.Text = "";
lblTax.Text = "";
lblTotal.Text = "";
ShoppingCartTitle.InnerText = "Shopping Cart is Empty";
UpdateBtn.Visible = false;
CheckoutImageBtn.Visible = false;
}
if (!IsPostBack)
{
LoadGrid();
}
}
}
void LoadGrid()
{
// Load Cart Items.
using (ShoppingCartActions actions = new ShoppingCartActions())
{
var _db = new ProductContext();
string cartId = actions.GetCartId();
var cart = _db.ShoppingCartItems.Where(
c => c.CartId == cartId).ToList();
// Create DataTable for Colors
rstSize.Columns.Add("SizeName", typeof(string));
var row = rstSize.NewRow();
row["SizeName"] = "S";
row["SizeName"] = "M";
row["SizeName"] = "L";
row["SizeName"] = "XL";
row["SizeName"] = "2XL";
CartList.DataSource = cart;
CartList.DataBind();
// Hide DropDown Lists for rows that they are not needed for.
for (int i = 0; i < CartList.Rows.Count; i )
{
DropDownList sizeDDL = CartList.Rows[i].FindControl("Sizeddl") as DropDownList;
DropDownList colorDDL = CartList.Rows[i].FindControl("ColorNameddl") as DropDownList;
IOrderedDictionary rowValues = new OrderedDictionary();
rowValues = GetValues(CartList.Rows[i]);
var _prodID = Convert.ToInt32(rowValues["ProductID"]);
var _prod = (from c in _db.Products
where c.ProductID == _prodID
select c.CategoryID).FirstOrDefault();
if (_prod != 1)
{
sizeDDL.Visible = false;
colorDDL.Visible = false;
}
}
}
}
我的行資料系結：
protected void CartList_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
DataRowView gData = (DataRowView)e.Row.DataItem;
// Populate and select Color from DB.
DropDownList sizeDDL = (DropDownList)e.Row.FindControl("Sizeddl");
sizeDDL.DataSource = rstSize;
sizeDDL.DataBind();
sizeDDL.Items.Insert(0, new ListItem("Select Size", "0"));
sizeDDL.SelectedValue = gData["SizeName"].ToString();
// Load Color DDL
var _size = sizeDDL.SelectedItem.Text;
int _prod = Convert.ToInt32(e.Row.Cells[0].Text);
var _db = new ProductContext();
var qryColor = (from p in _db.ProductAttributes
join c in _db.Colors
on p.ColorID equals c.ColorID
where p.SizeName == _size & p.ProductID == _prod
select new { p.ColorID, c.ColorName }).Distinct().ToList();
DropDownList colorDDL = (DropDownList)e.Row.FindControl("ColorNameddl");
// Create DataTable for Colors
DataTable rstColor = new DataTable();
rstColor.Columns.Add("ColorID", typeof(int));
rstColor.Columns.Add("ColorName", typeof(string));
foreach(var item in qryColor)
{
var row = rstColor.NewRow();
row["ColorID"] = item.ColorID;
row["ColorName"] = item.ColorName;
rstColor.Rows.Add(row);
}
// Bind Color Drop Down List to DataTable.
colorDDL.DataSource = rstColor;
colorDDL.DataBind();
colorDDL.Items.Insert(0, new ListItem("Select Color", "0"));
colorDDL.SelectedValue = gData["ColorName"].ToString();
}
}
我的 SelectedIndexChanged
protected void Sizeddl_SelectedIndexChanged(object sender, EventArgs e)
{
DropDownList sizeDDL = (DropDownList)sender;
GridViewRow gRow = (GridViewRow)sizeDDL.NamingContainer;
string strSize = sizeDDL.SelectedItem.Text;
DropDownList colorDDL = (DropDownList)gRow.FindControl("ColorNameddl");
if (strSize != "Choose one")
{
using (ProductContext context = new ProductContext())
{
int _prodID = Convert.ToInt32(gRow.Cells[0].Text);
var _size = sizeDDL.SelectedItem.Text;
var qryColor = (from p in context.ProductAttributes
join c in context.Colors
on p.ColorID equals c.ColorID
where p.SizeName == _size & p.ProductID == _prodID
select new { p.ColorID, c.ColorName }).Distinct().ToList();
if (qryColor.Count > 0)
{
colorDDL.DataSource = qryColor;
colorDDL.DataTextField = "ColorName";
colorDDL.DataValueField = "ColorID";
colorDDL.DataBind();
colorDDL.Items.Insert(0, new ListItem("Select Color", "0"));
colorDDL.Enabled = true;
}
else
{
colorDDL.Items.Clear();
colorDDL.Items.Insert(0, new ListItem("No Colors Available", "0"));
colorDDL.Enabled = false;
}
}
}
}
uj5u.com熱心網友回復：
如果您在第一行進行選擇
通過“選擇”，我們假設進行更改 - 或選擇/更改組合框中的值，對嗎？
我想保持選擇，直到所有 DropDownLists 都被選中并將更改保存到資料庫。任何幫助將不勝感激。
網格視圖將并且應該處理頁面上的回發。畢竟，即使在 GV 之外，任何舊按鈕或控制元件都可以并且將會導致回傳。
沒有理由讓用戶更改任何網格行，包括下拉串列 (DDL) 應該很重要。并且對一行的操作不應影響對其他行的操作。GV 的所謂“視圖”狀態是自動的，在大多數情況下您不必擔心。
因此，根本不清楚您為什么發布“添加行”，因為所有這些問題都集中在編輯或更改當前行上。（對我們來說，比如下周或任何時候，我們可以查看或處理創建的行，但現在讓我們專注于對給定行的更改，以及為什么由于某種原因您會在其他行中看到效果 - 您不應該看到這個。
名列榜首？
雖然控制 - 包括 GV 可以而且應該毫無問題地處理回發？
如果回發導致重新系結網格，則情況并非如此。如果發生這種情況，那么您將遇到問題。
那么，在榜單上名列前茅？
您忽略了加載 GV 的方式/時間/地點。（最重要的部分！！！！）。
下一個？
您不想也不需要在 GV 中顯示行 PK id。這些數字不僅對最終用戶毫無意義，而且還存在安全風險 - PK 行號不需要顯示，實際上甚至不需要包含在行標記中。我們可以再次將這個問題留到另一天，但您可以（并且應該考慮）使用 DataKeys 進行行 PK id 操作。我們假設資料庫中沒有重復的 PK 行 ID，對嗎？換句話說，請確保您的資料中有一個資料庫行 PK“id”。
因此，您將來可以洗掉該 ProductID。GV 具有處理 PK 行 ID 的特殊功能 - 我們應該使用它。（資料鍵）
好的，既然我們已經清除了上述內容？
在頁面加載事件中，我們需要加載 GV，但僅在第一頁加載時 - 之后，我們無法重新加載 GV（再次系結），否則您將丟失您的更改和對 GV 的編輯。
此外，您可能需要考慮底部的保存按鈕 - 保存所有 gv 更改 - 代替逐行執行此操作。（但是，這里一次一件事）。
所以首先，加載 GV 的代碼應該在頁面加載中。
接下來，該代碼只能在第一次運行。
例如：
if (!IsPostBack)
{
code here to load GV
}
下一個？當 GV 加載了該資料時，您需要設定組合框和級聯。此外，每一行的這種設定應該發生在行資料系結事件中。
So, your posted code does look ok, but we missing how/when you load the GV.
And we don't see your save button either. But at this point, I would share your code that loads up the GV - this all important information is missing here.
So edit your question - show how and when you load the grid up - that's missing.
Also, why the row created event being used here to setup a event? Just put the event stub and definition in the markup.
You are free to drop in a plane jane button, or DDL or whatever into the GV. And you should wire up the events like all other controls.
So, remove that row created event stub - it might be wiring up events for the wrong row - but it not required, and is a high risk adventure.
So, just do this:
So, for a button, or DDL in the GV? You can't double click on a button (to create a click event), and you can't display the property sheet to add events. But you can in markup just type in the event name, hit "=", and note how above intel-sense pops up a option to create the event. So, add the event that way. And after you select create new event, then you can flip over to code behind - you see the new event stub, and add your code to that stub. The GV uses internal information to wire up each row events - you may well be messing this up.
So, I would remove your row added - as we don't have details about that code and how/when you add a row, but 100% elimination of the row created event, and wiring up a click event will go a long way to elimination of any issues here - this would be especially the case if your row add event "copy's" controls - you might be copy the the DDL object when you do this, and that again will cause issues. In other words you may have the same object for two rows - changes to one will effect the other.
So, dump your row add event, and add the event directly in markup for the ddl as per above.
So, for buttons on each row, or whatever? You can still (and should) use markup to add those events - not code unless no other means exists to do so.
Edit: Working example
So, say this markup:
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataKeyNames="ID"
CssClass="table"
Width="30%" OnRowDataBound="GridView1_RowDataBound">
<Columns>
<asp:BoundField DataField="Firstname" HeaderText="Firstname" />
<asp:BoundField DataField="LastName" HeaderText="LastName" />
<asp:TemplateField HeaderText="Select Hotel City">
<ItemTemplate>
<asp:DropDownList ID="cboCity" runat="server" Width="120px" Height="26px"
DataTextField = "City"
DataValueField = "City"
AutoPostback="true"
OnSelectedIndexChanged="cboCity_SelectedIndexChanged"
>
</asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Select Hotel">
<ItemTemplate>
<asp:DropDownList ID="cboHotels" runat="server" Width="210px" Height="26px"
DataValueField ="ID"
DataTextField ="HotelName">
</asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Nights" >
<ItemTemplate>
<asp:TextBox ID="txtNights" runat="server" Style="text-align:right"
Text='<%# Eval("Nights") %>' Width="70px" >
</asp:TextBox>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
We will cascade city combo to restrict Hotels in 2nd combo.
So, our code to load:
DataTable rstCity = new DataTable();
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
LoadGrid();
}
void LoadGrid ()
{
// load up City list for combo box - all rows (scope = page)
SqlCommand cmdSQL = new SqlCommand("SELECT City from City ORDER BY City");
rstCity = MyRstP(cmdSQL);
// load up the grid
cmdSQL.CommandText = "SELECT * from People ORDER BY FirstName";
GridView1.DataSource = MyRstP(cmdSQL);
GridView1.DataBind();
}
We have this:
Note how we did NOT risk trying to set the DDL's in the markup - since we cascading - there will be way too many issues.
So, of course we have row data bound - and that sets up the two DDL's. (we setup the cascade AND ALSO set their values.
We have this:
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
DataRowView gData = (DataRowView)e.Row.DataItem; // get the row data
// load the city combo box
DropDownList cboCity = (DropDownList)e.Row.FindControl("cboCity");
cboCity.DataSource = rstCity;
cboCity.DataBind();
// add blank row for city
cboCity.Items.Insert(0, new ListItem("Select City", ""));
cboCity.SelectedValue = gData["City"].ToString(); // set value of Current city
// now load Hotel combo box - but cascade from above City cbo
string strSQL = @"Select ID, HotelName From tblHotels WHERE City = @City "
" ORDER BY HotelName";
SqlCommand cmdSQL = new SqlCommand(strSQL);
cmdSQL.Parameters.Add("@City", SqlDbType.NVarChar).Value = gData["HotelCity"].ToString();
DropDownList cboHotels = (DropDownList)e.Row.FindControl("cboHotels");
DataTable rstHotels = MyRstP(cmdSQL);
cboHotels.DataSource = rstHotels;
cboHotels.DataBind();
cboHotels.Items.Insert(0, new ListItem("Select Hotel", ""));
// set hotels combo to current selected
cboHotels.SelectedValue = gData["Hotel_id"].ToString();
}
}
So, the only part left is the first DDL post-back and cascade code. We have this:
protected void cboCity_SelectedIndexChanged(object sender, EventArgs e)
{
// city changed, so cascade Hotel cbo
DropDownList cboCity = (DropDownList)sender;
GridViewRow gRow = (GridViewRow)cboCity.NamingContainer;
// filter hotels to current city
string strCity = cboCity.SelectedItem.Text;
DropDownList cboHotels = (DropDownList)gRow.FindControl("cboHotels");
if (strCity != "Select City")
{
SqlCommand cmdSQL = new
SqlCommand(@"SELECT * from tblHotels WHERE City = @City ORDER BY HotelName");
cmdSQL.Parameters.Add("@City", SqlDbType.NVarChar).Value = strCity;
cboHotels.DataSource = MyRstP(cmdSQL);
cboHotels.DataBind();
cboHotels.Items.Insert(0, new ListItem("Select Hotel", ""));
}
}
So, with above? I don't see how it is possible that some "other" row gets effected here (unless you have some other code that attempts to mess around with the rows, or inserts a row into the GV. If you going to insert a row, then insert at the database level - and re-bind the GV. But, inserting is a separate issue.
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