c#-从Gridview中的下拉列表中永久删除项目

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我在Gridview中有dropdownList,

<asp:TemplateField HeaderText="Leave Category" >
    <ItemTemplate>
        <asp:DropDownList ID="LCList" runat ="server"  AutoPostBack="true" OnSelectedIndexChanged="LCList_TextChanged"/>
    </ItemTemplate>
</asp:TemplateField>

并添加诸如

protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        DropDownList LCList = (e.Row.FindControl("LCList") as DropDownList);
        LCList.Items.Insert(0, new ListItem("casual Leave"));
        LCList.Items.Insert(1, new ListItem("sick Leave"));
        LCList.Items.Insert(2, new ListItem("LOP"));
    }
}

如果我一次选择LOP,则应将其从网格的选定行下拉列表中删除.它不会再显示.

上面的代码正在工作.但是,如果我刷新页面,它将显示

如何解决呢？

是否需要在其他任何事件中创建商品？

解决方法:

之所以显示,是因为您必须将DropDownList中删除的值存储在某个地方,例如Session.您将必须保存行号和删除的值,然后在构建GridView时将DropDown中的值与已删除的值进行比较.

//create a list with keyvalue pairs to hold the removed items
public static List<KeyValuePair<int, string>> itemsRemoved = new List<KeyValuePair<int, string>>();

protected void Page_Load(object sender, EventArgs e)
{
    //check if the session with the removed items exists and if so cast back to a list
    if (Session["itemsRemoved"] != null)
    {
        itemsRemoved = Session["itemsRemoved"] as List<KeyValuePair<int, string>>;
    }

    //bind the gridview
    if (!Page.IsPostBack)
    {
        GridView1.DataSource = Common.LoadFromDB();
        GridView1.DataBind();
    }
}

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    //check if the row is a normal datarow
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        DropDownList LCList = (e.Row.FindControl("LCList") as DropDownList);

        //create an array with the dropdown option for easier looping
        string[] listItems = new string[] { "casual Leave", "sick Leave", "LOP" };

        for (int i = 0; i < listItems.Length; i++)
        {
            bool wasRemoved = false;

            //check if the listitem was remove for this row
            for (int j = 0; j < itemsRemoved.Count; j++)
            {
                if (e.Row.RowIndex == itemsRemoved[j].Key && listItems[i] == itemsRemoved[j].Value)
                {
                    wasRemoved = true;
                }
            }

            //if not removed, add it to the dropdownlist
            if (wasRemoved == false)
            {
                LCList.Items.Insert(LCList.Items.Count, new ListItem(listItems[i]));
            }
        }
    }
}

protected void LCList_SelectedIndexChanged(object sender, EventArgs e)
{
    //cast the sender back to a dropdownlist
    DropDownList LCList = sender as DropDownList;

    //get tne namingcontainer from the dropdownlist to get the rownumber
    GridViewRow row = (GridViewRow)LCList.NamingContainer;
    int rowIndex = row.RowIndex;

    //create a new keyvalue pair with the correct rowindex and selected value
    KeyValuePair<int, string> kv = new KeyValuePair<int, string>(rowIndex, LCList.SelectedValue);

    //add it to the list with removals
    itemsRemoved.Add(kv);

    //remove from the dropdownlist immediately
    LCList.Items.RemoveAt(LCList.SelectedIndex);
}

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