Question

问题和说明：

我有一个GridView，在RowDataBound上以编程方式将DropDownLists添加到每个单元格。

DropDownLists都有Data Sources。

当我按下“保存”按钮时，它意味着读取DropDownLists中的所有selecteditems并将它们保存到数据库中。

但是，当我单击按钮时，它会导致postback并删除GridView中的所有控件，因此，在我的button_click事件中找不到任何控件。

在提出问题并尝试使用不同的技术尝试将下拉列表存储在缓存/会话状态等之后，我似乎无法在单击按钮时保留下拉列表或数据。

因此，我现在正在尝试添加UpdatePanel并使用AJAX来尝试停止刷新GridView。

我的尝试是这样的：

                         <asp:GridView ID="gv_Rota" runat="server" AutoGenerateColumns="false"  OnRowDataBound="gv_Rota_RowDataBound">
                                    <HeaderStyle BackColor="#6a3d98" ForeColor="White" Height="20" />
                                    <RowStyle HorizontalAlign="Center" Height="20px" Width="100px" />
                                    <AlternatingRowStyle Height="20px" />
                                </asp:GridView>
                            </div>

                            <asp:Label ID="lbl_NameOfRota" runat="server" Text="New rota name:"></asp:Label>
                            <input runat="server" id="txt_RotaName" />

                            <asp:UpdatePanel runat="server" ID="RotaUpdatePanel">
                                <ContentTemplate>
                            <asp:Button ID="btn_AddRota" runat="server" Text="Add" OnClick="btn_AddRota_Click" CssClass="ButtonAdminPage" />
                                    </ContentTemplate>
                            </asp:UpdatePanel>

正如您所看到的，我只将UpdatePanel放在我的按钮周围，但是，它仍然似乎刷新了GridView并删除了所有控件。

问题：

首先，为什么我的尝试不起作用？

其次，我如何使用AJAX和更新面板解决这个问题，还是有另一种方法可以让我得到我需要的东西？（记住，如果有其他建议，我可能已经尝试过了。）

编辑2：

提供的代码：

这是我绑定DropDownLists的时候：

 protected void gv_Rota_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        for (int i = 1; i <= ColumnCount; i++)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                int day = e.Row.RowIndex;
                day += 1;
                ddlShift = new DropDownList();
                ddlShift.ID = "ddlShift" + "WK" + i.ToString() + "DAY" + day.ToString();
                ddlShift.DataSource = DCListOfShifts;
                ddlShift.DataValueField = "SHIFT_ID";
                ddlShift.DataTextField = "SHIFT_NAME";
                ddlShift.Attributes.Add("Place", i.ToString());
                ddlShift.DataBind();
                ddlShift.Items.Insert(0, new ListItem("Shift..."));
                ddlShift.CssClass = "ddl_rotamanager";
                e.Row.Cells[i].Controls.Add(ddlShift);
            }
        }          
    }

这是我根据传递的列数创建GridView的时候：

 private void BindGrid(int Amount)
    {
            gv_Rota.DataSource = null;
            gv_Rota.Columns.Clear();

        BoundField bfield = new BoundField();
        bfield.HeaderText = "Days";
        bfield.DataField = "Days";
        gv_Rota.Columns.Add(bfield);

        for (int i = 0; i < Amount; i++)
        {
            int week = i + 1;
            string sWeek = "Week " + week.ToString();

            TemplateField tfield = new TemplateField();
            tfield.HeaderText = sWeek;
            gv_Rota.Columns.Add(tfield);
        }

        DataTable dt = new DataTable();
        dt.Columns.Add(new DataColumn("Days", typeof(string)));
        dt.Rows.Add("M");
        dt.Rows.Add("T");
        dt.Rows.Add("W");
        dt.Rows.Add("T");
        dt.Rows.Add("F");
        dt.Rows.Add("S");
        dt.Rows.Add("S");
        gv_Rota.DataSource = dt;
        gv_Rota.DataBind();

    }

这是我获取选定数量的列并调用方法来创建GridView的地方，我还将数量存储在缓存中：

protected void ddl_RotaAmountOfWeeks_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (IsPostBack)
        {
            int Amount;
            int.TryParse(ddl_RotaAmountOfWeeks.SelectedItem.ToString(), out Amount);

            ColumnCount = Amount;

            Cache.Add("columnCount", ColumnCount, null, Cache.NoAbsoluteExpiration, new TimeSpan(0, 60, 0), CacheItemPriority.Default, null);

            BindGrid(Amount);
        }
    }

按钮代码：

 protected void btn_AddRota_Click(object sender, EventArgs e)
    {
        //My first attempt at trying to save the GridView, realising I Cache'd the GridView before selecting items.
        //gv_Rota = (GridView)Cache["cacheGridView"];

        //Set of the size of the array to the amount of rows * colums 
        //this will be the maximum amount of events added
        int arraysize = gv_Rota.Rows.Count * (int)Cache["columnCount"];

        //the current array item being added
        int arrayitem = 0;

        //Finally an array of ROTA_EVENTS to pass to WCF
        wsPersonnel.DC_WFM_ROTA_EVENTS[] arrayofRotaEvents = new wsPersonnel.DC_WFM_ROTA_EVENTS[arraysize];


        foreach (GridViewRow row in gv_Rota.Rows)
        {
            for (int i = 1; i <= (int)Cache["columnCount"]; i++)
            {
                int day = row.RowIndex;
                day += 1;
                DropDownList DDL1 = (DropDownList)gv_Rota.Rows[row.RowIndex].Cells[i].FindControl("ddlShiftWK" + i.ToString() + "DAY" + day.ToString());

                wsPersonnel.DC_WFM_ROTA_EVENTS dcEvent = new wsPersonnel.DC_WFM_ROTA_EVENTS
                {
                    SHIFT_ID = DDL1.SelectedItem.Value,
                    WEEK = i,
                    WEEKSpecified = true,
                    DAY = day,
                    DAYSpecified = true,
                };
                arrayofRotaEvents[arrayitem++] = dcEvent;
            }
        }

        wsP.AddRota(new wsPersonnel.DC_WFM_ROTA
        {
            ROTA_NAME = txt_RotaName.Value,
            PERIOD_TYPE = 1,
            PERIOD_TYPESpecified = true,
            PERIOD_AMOUNT = ColumnCount,
            PERIOD_AMOUNTSpecified = true,
            ROTA_EVENTS = arrayofRotaEvents
        });
    }

GridView的示例：

enter image description here

Answer 1

如果要在更新面板内单击按钮上停止回发，则可以尝试此

<asp:UpdatePanel runat="server" ID="RotaUpdatePanel" UpdateMode="Conditional">
   <ContentTemplate>
    <asp:Button ID="btn_AddRota" runat="server" Text="Add" OnClick="btn_AddRota_Click" CssClass="ButtonAdminPage" ClientIDMode="AutoID"/>
   </ContentTemplate>
   <Triggers>
     <asp:AsyncPostBackTrigger ControlID="btn_AddRota" EventName="Click" />
   </Triggers>
</asp:UpdatePanel>

不在UpdatePanel中时仍会刷新GridView

1 个答案: