如何在启用了分页的网格视图中维护控件的状态

本文关键字：视图 维护 控件 状态 网格 启用 分页 | 更新日期: 2023-09-27 18:00:43

我有一个由4列组成的网格视图，其中一列为Approve。Approve有一个复选框，绑定后将对数据集的所有行重复该复选框。我已经使allowpageg=true&pageindexsize为10。现在，假设我选中了第2行和第5行的复选框，然后移到第2页，回到第1页，我在第1页选中的（第2行）复选框将重置为未选中状态。我知道原因，这是由于我们对onpageindexchangeing事件所做的网格视图的绑定。但是，即使我们从一个页面移动到另一个页面，是否有任何方法可以保持复选框的状态。

感谢

如何在启用了分页的网格视图中维护控件的状态

您可以使用Session来维护这些值。一页索引更改事件，您需要向会话添加值并重新绑定复选框。

这里有几个链接可以帮助你

  1. http://forums.asp.net/p/1368550/2852029.aspx
  2. http://myaspsnippets.blogspot.com/2010/08/maintaining-state-of-checkboxes-while.html

Try，（您必须将两个事件Checkbox_Checked和Checkbox_PreRender设置为网格中的Checkbox控件。此外，还必须在网格中设置DataKey，以便Checks数组中有索引。）

protected bool[] Checks
{
    get { return (bool[])(ViewState["Checks"] ?? new bool[totalLengthOfDataSource]); }
    set { ViewState["Checks"] = value; }
}
protected void Checkbox_Checked(object sender, EventArgs e)
{
    CheckBox cb = (CheckBox)sender;
    bool[] checks = Checks;
    checks[(int)GetRowDataKeyValue(sender)] = cb.Checked;
    Checks = checks;
}
protected void Checkbox_PreRender(object sender, EventArgs e)
{
    CheckBox cb = (CheckBox)sender;
    bool[] checks = Checks;
    cb.Checked = checks[(int)GetRowDataKeyValue(sender)];
}

这些在静态GridViewUtils类中效果最好。

public static GridViewRow GetRow(object sender)
{
    Control c = (Control)sender;
    while ((null != c) && !(c is GridViewRow))
        c = c.NamingContainer;
    return (GridViewRow)c;
}
/// <summary>
/// Get the Grid the row is in
/// </summary>
/// <param name="row"></param>
/// <returns></returns>
public static GridView GetGrid(this GridViewRow row)
{
    Control c = (Control)row;
    while ((null != c) && !(c is GridView))
        c = c.NamingContainer;
    return (GridView)c;
}
/// <summary>
/// Get the ID field value based on DataKey and row's index
/// </summary>
/// <param name="sender">Any web-control object in the grid view</param>
/// <returns></returns>
public static object GetRowDataKeyValue(object sender)
{
    try
    {
        GridViewRow row = GetRow(sender);
        GridView grid = row.GetGrid();
        return grid.DataKeys[row.RowIndex].Value;
    }
    catch
    {
        return null;
    }
}

另一种方法：

在名为"userSelected"（或类似的）的可绑定对象上创建一个bool属性根据可绑定列表对象的对象ID创建索引器在grid_RowDataBound上，将可绑定对象的ID作为属性添加到复选框中在grid_RowDataBound上，还将复选框的checked属性设置为obj.userSelected在checkch_CheckChaged中，使用索引器设置可绑定对象的userSelected属性

感谢

我尝试了@Chuck的PreRender技术，但对我不起作用（VS2005、ASP.net2、SQLsrv2005）。也许技术太老了，但这就是客户所拥有的。

所以我尝试了简单的myaspsnippets技术，经过一些修改，效果非常好！

我的Gridview

                <asp:GridView ID="gvFTUNSENT" runat="server" 
                    AutoGenerateColumns="False" CellPadding="4" ForeColor="Black" AllowSorting="False" CssClass="gvCSS" Width="100%"
                    DataKeyNames="StudentID,StudentUnitID" DataSourceID="sdsFTUNSENT" 
                    GridLines="None" AllowPaging="True" PageSize="10" BackColor="White" BorderColor="#DEDFDE" BorderStyle="None" BorderWidth="1px" 
                    OnPageIndexChanged="GridView_PageIndexChanged" 
                    OnPageIndexChanging="GridView_PageIndexChanging">
                    <RowStyle Wrap="True" Height="48px" />
                    <Columns>
...etc...
                    </Columns>
                    <FooterStyle BackColor="#6B696B" Font-Bold="True" ForeColor="White" Height="100%" />
                    <PagerStyle CssClass="cssPager" BackColor="#6B696B" ForeColor="White" HorizontalAlign="Left" Height="100%" />
                    <HeaderStyle BackColor="#6B696B" Font-Bold="True" ForeColor="White" />
                </asp:GridView>

我使用的分页方法有：

protected void GridView_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
    GridView gv = (GridView)sender;
    //saves a "copy" of the page before it's changed over to the next one
    SavePageState(gv);
    gv.PageIndex = e.NewPageIndex;
    gv.DataBind();
}

和

    protected void GridView_PageIndexChanged(object sender, EventArgs e)
    {
...your code to handle anything after the page has changed
                    gv.DataSource = dt;
                    gv.DataSourceID = null;
                    gv.DataBind();
                    //reload any checkboxes that were session saved in the page
                    LoadPageState(gv);
                }
            }
        }
    }

因此SAVE和LOAD方法如下：

private void SavePageState(GridView gv)
{
    ArrayList categoryIDList = new ArrayList();
    Int32 index = -1;
    foreach (GridViewRow row in gv.Rows)
    {
        HiddenField hfStudentUnitID = (HiddenField)row.FindControl("hfStudentUnitID");
        if (hfStudentUnitID != null)
        {
            if (hfStudentUnitID.Value.Length > 0)
            {
                index = Convert.ToInt32(hfStudentUnitID.Value.ToString()); //gv.DataKeys[row.RowIndex]["StudentUnitID"];
                bool result = ((CheckBox)row.FindControl("cbSEND")).Checked;
                // Check in the Session
                if (Session["CHECKED_ITEMS"] != null)
                    categoryIDList = (ArrayList)Session["CHECKED_ITEMS"];
                if (result)
                {
                    if (!categoryIDList.Contains(index))
                        categoryIDList.Add(index);
                }
                else
                    categoryIDList.Remove(index);
            }
        }
    }
    if (categoryIDList != null && categoryIDList.Count > 0)
        Session["CHECKED_ITEMS"] = categoryIDList;
}

和

private void LoadPageState(GridView gv)
{
    ArrayList categoryIDList = (ArrayList)Session["CHECKED_ITEMS"];
    if (categoryIDList != null && categoryIDList.Count > 0)
    {
        foreach (GridViewRow row in gv.Rows)
        {
            HiddenField hfStudentUnitID = (HiddenField)row.FindControl("hfStudentUnitID");
            if (hfStudentUnitID != null)
            {
                if (hfStudentUnitID.Value.Length > 0)
                {
                    Int32 index = Convert.ToInt32(hfStudentUnitID.Value.ToString()); //gv.DataKeys[row.RowIndex]["StudentUnitID"];
                    if (categoryIDList.Contains(index))
                    {
                        CheckBox myCheckBox = (CheckBox)row.FindControl("cbSEND");
                        myCheckBox.Checked = true;
                    }
                }
            }
        }
    }
}

为了实现这一点，您需要将Paging方法调用放入GridView中，将CheckBox ID从cbSEND更改为您所使用的，并将HiddenFields指向其他具有行唯一标识符的控件或值不要使用RowIndex，因为它在GridView中的整个数据长度中都不是唯一的。

工作起来很有魅力！

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