c# - 当 DropDownList Filter 的值不是 ALL 时，如何删除 GridView 中的整个第一列？

Question

我有以下复杂的 asp.net 代码结构:

1. DropDownList 作为过滤器
2. 转发器
3. 在 Repeater 内部:我有 HiddenField 和 GridView

我想当 Filter 的值设置为 All 时，应该删除第一列。问题是我正在使用负责生成三个 GridView 的 StoredProcedure，这样我将 GridView 放在 Repeater 中。

ASP.NET 代码:

<asp:DropDownList ID="ddlDivision" runat="server" AppendDataBoundItems="True" 
        AutoPostBack="True" DataSourceID="sqlDataSourceDivision" DataTextField="DivisionName" 
        DataValueField="DivisionName"  
        Width="275px" EnableViewState="False">
        <asp:ListItem Value="%">All</asp:ListItem>
    </asp:DropDownList>


     <br />  <br />  
        <asp:Repeater ID="Repeater1" runat="server" DataSourceID="SqlDataSource1">
            <ItemTemplate>

                <asp:HiddenField ID="HiddenField1" runat="server" Value='<%# Eval("GroupID")%>' />

                <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
                                    ConnectionString="<%$ ConnectionStrings:testConnectionString %>" 
                                    SelectCommandType="StoredProcedure" SelectCommand="kbiReport"
                                    FilterExpression="[DivisionName] like '{0}%'">

                    <FilterParameters>
                        <asp:ControlParameter ControlID="ddlDivision" Name="DivisionName" 
                                                 PropertyName="SelectedValue" Type="String" />
                    </FilterParameters>

                    <SelectParameters>
                        <%--ControlParameter is linked to the HiddenField above to generate different GridView based on different values 
                            of GroupID--%>
                        <asp:ControlParameter ControlID="HiddenField1" Name="GroupID" PropertyName="Value" />
                    </SelectParameters>
                </asp:SqlDataSource>
                <div style="width:700px; overflow:auto; overflow-y:hidden;">

                <asp:GridView ID="GridView1" runat="server" 
                                AllowSorting="True" 
                                CellPadding="3" 
                                DataSourceID="SqlDataSource1" 
                                ClientIDMode="Static" class="fixedTables" Width="600" AutoGenerateColumns="true"
                                AlternatingRowStyle-CssClass="alt"
                                RowStyle-HorizontalAlign="Center" 
                                OnRowDataBound="GridView1_RowDataBound" OnPreRender="GridView1_PreRender" OnRowCreated="GridView1_RowCreated"
                                OnDataBound="GridView1_DataBound">
                    <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
                    <HeaderStyle Font-Bold = "true" ForeColor="Black"/> 
                    <Columns>
                    </Columns>
                    <EditRowStyle BackColor="#999999" />
                    <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
                    <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
                    <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
                    <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
                    <SortedAscendingCellStyle BackColor="#E9E7E2" />
                    <SortedAscendingHeaderStyle BackColor="#506C8C" />
                    <SortedDescendingCellStyle BackColor="#FFFDF8" />
                    <SortedDescendingHeaderStyle BackColor="#6F8DAE" />
                </asp:GridView>
                </div>
                <br />
            </ItemTemplate>
        </asp:Repeater>

        <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
                           ConnectionString="<%$ ConnectionStrings:testConnectionString %>"
                           SelectCommand="SELECT DISTINCT GroupID FROM courses">
        </asp:SqlDataSource>

        <%--Filtering by Division--%>
        <asp:SqlDataSource ID="sqlDataSourceDivision" runat="server" 
        ConnectionString="<%$ ConnectionStrings:testConnectionString %>" 
        SelectCommand="SELECT [DivisionName] FROM [Divisions]"></asp:SqlDataSource>

代码隐藏:

protected void Page_Load(object sender, EventArgs e)
    {

        //Repeater1.DataBind();


    }


    //protected void Repeater1_ItemDataBound(object sender, RepeaterItemEventArgs e)
    //{
    //    if (e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.Item)
    //    {
    //        GridView gv = e.Item.FindControl("GridView1") as GridView;
    //        if (gv != null)
    //        {

    //            gv.DataBind();
    //            if (ddlDivision.SelectedValue != "ALL")
    //            {
    //                if (gv.Columns.Count > 0)
    //                    gv.Columns[0].Visible = false;
    //                else
    //                {
    //                    gv.HeaderRow.Cells[0].Visible = false;
    //                    foreach (GridViewRow gvr in gv.Rows)
    //                    {
    //                        gvr.Cells[0].Visible = false;
    //                    }
    //                }
    //            }

    //        }
    //    }

    //}



    //protected void ddlDivision_SelectedIndexChanged(object sender, EventArgs e)
    //{
    //    if (ddlDivision.SelectedItem.Text == "All")
    //    {
    //        GridView1.Columns[0].Visible = true;
    //    }
    //    else
    //    {
    //        GridView1.Columns[0].Visible = false;
    //    }
    //}

    //This method is for deleting the first column in the GridView
    protected void GridView1_RowCreated(object sender, GridViewRowEventArgs e)
    {
       // e.Row.Cells[0].Visible = false; // hides the first column
    }

    protected void GridView1_DataBound(object sender, EventArgs e)
    {
        //GridView GridView1 = (GridView)sender;
        //foreach (GridViewRow gvr in GridView1.Rows)
        //{
        //    if (ddlDivision.SelectedValue != "All")
        //    {
        //        gvr.Cells[0].Visible = false;

        //    }
        //}




    }


    //This function is for checking each cell in each row. 
    protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        //var gv = sender as GridView;
        //if (ddlDivision.SelectedValue == "All")
        //    gv.Columns[0].Visible = false;

        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            foreach (TableCell c in e.Row.Cells)
            {
                // Check if the cell vlaue = Yes
                // if it is Yes, the cell will be colored with Light Green 
                if (c.Text.Contains(", Yes"))
                {
                    c.BackColor = System.Drawing.Color.LightGreen;
                    c.Text = "•";
                }
                else if (c.Text.Contains(", NO"))
                {

                    c.Text = "";
                }
            }
        }

         //The following is for changing the color of headers in each GridView based on the value of the HiddenFild 
         //BTW, the value of the HiddenField is the value of the GroupID in Group Table in the Database 
        else if (e.Row.RowType == DataControlRowType.Header)
        {
            switch (((HiddenField)((GridView)sender).Parent.FindControl("HiddenField1")).Value)
            {
                case "1":
                    for (int i = 4; i < e.Row.Cells.Count; i++)
                        e.Row.Cells[i].BackColor = System.Drawing.Color.LightBlue;
                    break;

                case "2":
                    for (int i = 4; i < e.Row.Cells.Count; i++)
                        e.Row.Cells[i].BackColor = System.Drawing.Color.LightYellow;
                    break;

                case "3":
                    for (int i = 4; i < e.Row.Cells.Count; i++)
                        e.Row.Cells[i].BackColor = System.Drawing.Color.Orange;
                    break;
            }
        }

    }


    protected void GridView1_PreRender(object sender, EventArgs e)
    {
        var gv = sender as GridView;
        if (gv.Rows.Count > 0)
        {
            gv.UseAccessibleHeader = true;
            gv.HeaderRow.TableSection = TableRowSection.TableHeader;
        }
    }

我做了很多尝试，但都失败了，正如您在上面的后台代码中看到的那样。最后一次尝试是:

protected void Repeater1_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.Item)
    {
        GridView gv = e.Item.FindControl("GridView1") as GridView;
        if (gv != null)
        {

            gv.DataBind();
            if (ddlDivision.SelectedValue != "ALL")
            {
                if (gv.Columns.Count > 0)
                    gv.Columns[0].Visible = false;
                else
                {
                    gv.HeaderRow.Cells[0].Visible = false;
                    foreach (GridViewRow gvr in gv.Rows)
                    {
                        gvr.Cells[0].Visible = false;
                    }
                }
            }

        }
    }

}

我失败了。 谁能帮我解决这个问题？

Answer 1

I want when the value of Filter is setting to All, the fist column should be removed.

如果是这种情况，您肯定想要这样:

if (ddlDivision.SelectedValue == "ALL") { // hide column 0 } 

而不是这个:

if (ddlDivision.SelectedValue != "ALL") { // hide column 0 } 

使用 gv.Columns[0].Visible = false; 应该可以正常工作假设你有一个正确的引用你的 gv 对象 and您的 GridView 将其 AutoGenerateColumns 属性设置为 false。

您必须确保这一点，因为 AutoGenerateColumns="true" 是 GridView 默认值，在这种情况下，GridView.Columns.Count 将始终为 0。如果您尝试引用 .Columns[x] 它将抛出“索引超出范围”。异常。

更多信息在这里:https://stackoverflow.com/a/3819831/441574

更新:

当您使用 AutoGenerateColumns="true" 时，您可以使用 GridView 的 RowDataBound 事件隐藏您的列:

创建事件处理程序:

如果您的 GridView 是静态(在您的 .aspx 页面上声明)，请将其添加到其声明中:OnRowDataBound="gv_RowDataBound"

如果您的 GridView 是以编程方式创建，请添加 RowDataBound 事件处理程序:gv.RowDataBound += new GridViewRowEventHandler(gv_RowDataBound);

然后添加您的 RowDataBound 事件:

protected void gv_RowDataBound(object sender, GridViewRowEventArgs e) 
{ 
    ...
    if (e.Row.RowType != DataControlRowType.Pager) 
    {
        if (ddlDivision.SelectedItem.Text != "ALL")
        {
           // only check for pager row, all other rows including header/footer should be hidden
           e.Row.Cells[0].Visible = false; 
        }
    }
    ...    
}