在GridView中的分页期间维护复选框的状态 [英] Maintaining the state of check boxes during pagination in gridview

问题描述

大家好，

我成功地将代码添加到页面中，以在分页期间维护网格视图中复选框的状态，但是出现了一个非常不同的问题.如果我在第一页上选中了一些复选框，然后在第二页上选中了某些复选框，然后返回到第一页，那么我看到的是，与我相比，自动选中的复选框数量更多.我不知道我要去哪里错了！
我完全按照此链接中的逻辑和代码片段进行操作:

维护选定复选框的状态在GridView内部的不同页面中 [ ^ ]

谁能帮助我，这对我的项目来说确实非常紧急和重要.
谢谢

Hi All,

I successfully added the code to my page for maintaining the state of check boxes in grid view during pagination but got a very different issue. if I select some check boxes on the first page and than go on second page and select some check boxes there and return back to first page, what I see is that there are more number of check boxes selected automatically as compared to I did. I don''t know where I am going wrong !
I exactly followed the logic and code snippet as in this link :

Maintaining States of Selected CheckBoxes in Different Pages inside the GridView[^]

Can anyone please help me,,,It is really urgent and important for my project.
Thank you

推荐答案

可以用多种方法来完成，但是基本上每次核对CheckBox时，都必须将其状态保存到现在为Checked或Unchecked的位置.然后，在每次重新绑定数据后，您可以将该状态从Session或ViewState中拉出，并重新设置CheckBoxes的状态.这是我如何维护状态的示例:

ASPX:

This can be done a variety of ways, but basically everytime a CheckBox is checked, you must save its state somewhere that it is now Checked or Unchecked. Then after every re-bind of your data, you can pull this state out of the Session or ViewState and re-set the state of the CheckBoxes. Here''s an example of how I would maintain the state:

ASPX:

<asp:gridview id="gvProducts" runat="server" allowpaging="True" autogeneratecolumns="False" xmlns:asp="#unknown">
datakeynames="ProductID" datasourceid="ldsProducts" style="margin-top: 20px;"
onpageindexchanging="gvProducts_PageIndexChanging" onrowdatabound="gvProducts_RowDataBound">
    <columns>
        <asp:templatefield headertext="Select">
            <itemtemplate>
                    <asp:checkbox id="chkSelect" runat="server" />
            </itemtemplate>
        </asp:templatefield>
        <asp:boundfield datafield="ProductID" headertext="ProductID" insertvisible="False">
readonly="True" sortexpression="ProductID" />
        <asp:boundfield datafield="ProductName" headertext="ProductName" sortexpression="ProductName" />
    </asp:boundfield></columns>
</asp:gridview>
<asp:linqdatasource id="ldsProducts" runat="server" contexttypename="LinqToSql.NorthwindDataContext" xmlns:asp="#unknown">
tablename="Products">
</asp:linqdatasource>

背后的代码:

Code Behind:

public partial class GridView_MaintainCheckBoxStateWhenPaging : System.Web.UI.Page
{
        private List<int> ProductIDs
        {
                get
                {
                        if (this.ViewState["ProductIDs"] == null)
                        {
                                this.ViewState["ProductIDs"] = new List<int>();
                        }

                        return this.ViewState["ProductIDs"] as List<int>;
                }
        }

        protected void SelectDeselect(object sender, CommandEventArgs e)
        {
                foreach (GridViewRow gvr in gvProducts.Rows)
                {
                        CheckBox chkSelect = gvr.FindControl("chkSelect") as CheckBox;

                        if (chkSelect != null)
                        {
                                chkSelect.Checked = e.CommandName.Equals("SelectAll");
                        }
                }
        }

        protected void gvProducts_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            foreach (GridViewRow gvr in gvProducts.Rows)
            {
                CheckBox chkSelect = gvr.FindControl("chkSelect") as CheckBox;
                if (chkSelect != null)
                {
                    int productID = Convert.ToInt32(gvProducts.DataKeys[gvr.RowIndex]["ProductID"]);

                    if (chkSelect.Checked && !this.ProductIDs.Contains(productID))
                    {
                        this.ProductIDs.Add(productID);
                    }
                    else if (!chkSelect.Checked && this.ProductIDs.Contains(productID))
                    {
                        this.ProductIDs.Remove(productID);
                    }
                }
            }
        }

        protected void gvProducts_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            GridViewRow gvr = e.Row;

            if (gvr.RowType == DataControlRowType.DataRow)
            {
                CheckBox chkSelect = gvr.FindControl("chkSelect") as CheckBox;
                if (chkSelect != null)
                {
                    int productID = Convert.ToInt32(gvProducts.DataKeys[gvr.RowIndex]["ProductID"]);
                    chkSelect.Checked = this.ProductIDs.Contains(productID);
                }
            }
        }
}

祝一切顺利.

--Amit

All the best.

--Amit

protected void btn_daily_send_all_Click(object sender, EventArgs e)
    {
        int flag = 0;
        gvAllClients.Visible = true;
        gvAllClients.AllowPaging = false; // this is where is disabled paging
        
        try
        {
            if ((txt_daily_from.Text != "") || (txt_daily_to.Text != ""))
            {
                
                string strSucessEmail = "";
                string strFailedEmail = "";

/* this is my some logic of checking date validations*/
                DateTime date_from_for_daily_email = Convert.ToDateTime(txt_daily_from.Text);
                DateTime date_to_for_daily_email = Convert.ToDateTime(txt_daily_to.Text);
                DateTime date_end = Convert.ToDateTime(ViewState["latest_date_port_uploaded"]);
                DateTime dt = Convert.ToDateTime(ViewState["date_last_mailed"]);
                DateTime date_start = choosing_first_date(ref dt);

              //here i traversed my gv

                foreach(GridViewRow row in gvAllClients.Rows)
                {


                    string strworkOrder = ((Label)(row.Cells[5].FindControl("lblWorkOrd"))).Text;
                    string strdata = ((Label)(row.Cells[6].FindControl("lblData"))).Text;
                    string strHSCODE = ((Label)(row.Cells[9].FindControl("lblHSCode"))).Text;
                    string strCombination = ((Label)(row.Cells[10].FindControl("lblComb"))).Text;
                    string strProd = ((Label)(row.Cells[11].FindControl("lblProd"))).Text;
                    string strProd_Not = ((Label)(row.Cells[12].FindControl("lblProd_not"))).Text;
                    string strActive = ((Label)(row.Cells[13].FindControl("lblActive"))).Text;
                    string strEmailId = ((Label)(row.Cells[14].FindControl("lblEmail"))).Text;
                    DateTime date_from_subscp = Convert.ToDateTime(((Label)(row.Cells[7].FindControl("lblfrom"))).Text);
                    DateTime date_to_subscp = Convert.ToDateTime(((Label)(row.Cells[8].FindControl("lblTo"))).Text);
                    CheckBox chk = (CheckBox)(row.Cells[30].FindControl("chkEmail_Single"));

                    if (strActive == "NO")
                    {
                        strFailedEmail += "" + strEmailId + ", ";
                    }


                    else if (strActive == "YES")   
                    {
                        //((date_from_for_daily_email < date_start) || 
                        if (date_to_for_daily_email > date_end)
                        {
                            lblMsg.Visible = true;
                            lblMsg.Text = "You cannnot select a date less than last mailed date and greater than " + date_end.ToString("dd-MMM-yyyy") + ".";
                        }
                        else if (date_from_for_daily_email > date_to_for_daily_email)
                        {
                            lblMsg.Visible = true;
                            lblMsg.Text = "Invalid date range. Please check the dates and than try again...";
                        }

                        else if (date_to_subscp < date_to_for_daily_email)
                        {
 // this is some of my logic to store the records of success and unsuccessful mails
                            strFailedEmail += "" + strEmailId + ", ";

                        }
                        else if (chk.Checked == true)
                        {
                            strFailedEmail += "" + strEmailId + ", ";
                        }

                        else
                        {
                            int iResult = bl_Query_for_admin.Query_Data_Email_Attachment(strworkOrder, strdata, date_from_for_daily_email, date_to_for_daily_email, strHSCODE, strCombination, strProd, strProd_Not, strEmailId);

                            if (iResult == 1)
                            {
                                if (flag == 0)
                                {
                                    bl_myAccount.insert_last_daily_email_date(date_to_for_daily_email);

                                    flag = 1;
                                }

                                strSucessEmail += "" + strEmailId + ", ";

                                lblMsg.Visible = true;

                                lblMsg.Text = "Email Sent Succesfully !!!";
                                continue;

                            }
                            else
                            {
                                continue;
                            }
                        }


                    }

                }

                btnLog.Visible = true;
                gvAllClients.Visible = true;
                inserting_mail_history(ref strSucessEmail, ref strFailedEmail);


            }
            else
            {
                lblMsg.Visible = true;
                lblMsg.Text = "Please enter a valid date for data mining...";
            }
        }
        catch (Exception ex)
        {

        }
    }

现在，我已经将我的gv绑定在回发ryt之外了...

I have binded my gv outside the postback ryt now Sir...

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