从一个GridView中进行多个选择，并在另一个GridView中显示数据

Question

我在行命令上对GridView有问题，并将数据堆叠在另一个GridView：

中

private List<DistributionStandardPackingUnitItems> tempDistSPUI
{
    get
    {
        if (ViewState["tempDistSPUI"] == null)
        {
            return new List<DistributionStandardPackingUnitItems>();
        }
        else
        {
            return (List<DistributionStandardPackingUnitItems>)ViewState["tempDistSPUI"];
        }
    }
    set
    {
        ViewState["tempDistSPUI"] = value;
    }
}
protected void gvSPU_OnRowCommand(object sender, GridViewCommandEventArgs e)
{
    int packagesNeeded = prodPackBLL.getPackagesNeededByDistributionID(distributionID);
    //Get selected standard packing name
    int rowNo = int.Parse(e.CommandArgument.ToString());
    SPUname = this.gvSPU.DataKeys[rowNo].Value.ToString();
    lblSPUname.Text = SPUname;
    //Get the record from view state
    itemList = tempDistSPUI;
    itemList = packBLL.getAllDistSPUItemByDistributionIDnSPUName(distributionID, SPUname);
    gvFinalised.DataSource = itemList;
    gvFinalised.DataBind();
    //Save the last record to view state
    this.tempDistSPUI = itemList;
}

说，当我第一次从gvSPU中选择一行时，它返回一个填充数据并在gvFinalised中显示的itemList。我要做的是，如果我从gvSPU中选择了另一行，则GVFINARISE中的先前记录仍将在那里，并从二次选择的行中堆叠另一个itemList，而不是先前删除记录并显示最新的itemList数据。

我正在使用viewState，但它不起作用。

编辑

protected void lbnAdd_Click(object sender, EventArgs e)
    {
        List<DistributionStandardPackingUnitItems> prodVariantDetail = new List<DistributionStandardPackingUnitItems>();
        int packagesNeeded = prodPackBLL.getPackagesNeededByDistributionID(distributionID);
        // get the last product variant IDs from ViewState
        prodVariantIDList = this.SelectedVariantDetailIDs;
        foreach (RepeaterItem ri in Repeater1.Items)
        {
            GridView gvProduct = (GridView)ri.FindControl("gvProduct");
            foreach (GridViewRow gr in gvProduct.Rows)
            {
                CheckBox cb = (CheckBox)gr.FindControl("cbCheckRow");
                //Prevent gvFinalised to store duplicate products
                if (cb.Checked && !prodVariantIDList.Any(i => i == gvProduct.DataKeys[gr.RowIndex].Value.ToString()))
                {
                    // add the corresponding DataKey to idList
                    prodVariantIDList.Add(gvProduct.DataKeys[gr.RowIndex].Value.ToString());
                }
            }
        }
        for (int i = 0; i < prodVariantIDList.Count; i++)
        {
            prodVariantDetail.Add(packBLL.getProdVariantDetailByID(prodVariantIDList[i]));
        }
        //Check if itemList and prodVariantDetail list contains any duplicate records
        var Gdupes = itemList.GroupBy(x => new { x.id }).Where(x => x.Skip(1).Any()).ToList();
        List<DistributionStandardPackingUnitItems> dupes = Gdupes.SelectMany(x => x).ToList();
        prodVariantDetail = itemList.Except(dupes).ToList();
        gvFinalised.DataSource = prodVariantDetail;
        gvFinalised.DataBind();
        foreach (GridViewRow gr in gvFinalised.Rows)
        {
            //Get the product packaging quantity by productName
            string name = gr.Cells[1].Text;
            int productQuantity = packBLL.getProductQuantityByName(name, distributionID);
            TextBox tb = (TextBox)gr.Cells[5].FindControl("tbQuantity");
            if (productQuantity == 0)
            {
                tb.Text = productQuantity.ToString();
            }
            else
            {
                tb.Text = (productQuantity / packagesNeeded).ToString();
            }
        }
        // save prodVariantIDList to ViewState
        this.SelectedVariantDetailIDs = prodVariantIDList;
    }
private List<string> SelectedVariantDetailIDs
    {
        get
        {
            if (ViewState["SelectedVariantDetailIDs"] == null)
            {
                return new List<string>();
            }
            else
            {
                return (List<string>)ViewState["SelectedVariantDetailIDs"];
            }
        }
        set
        {
            ViewState["SelectedVariantDetailIDs"] = value;
        }
    }

Answer 1

问题是以下行：

//Get the record from view state
itemList = tempDistSPUI; 
// here itemList will be replaced 
itemList = packBLL.getAllDistSPUItemByDistributionIDnSPUName(distributionID, SPUname);

首先，您将tempDistSPUI从ViewState分配到itemList，但随后在下一行中替换itemList。您需要将从packBLL.getAllDistSPUItemByDistributionIDnSPUName返回的元素添加到itemList，而不是替换itemList。这是我使用list.Addrange方法的方法：

itemList = tempDistSPUI; 
// add the returned elements to itemList
itemList.AddRange(packBLL.getAllDistSPUItemByDistributionIDnSPUName(distributionID, SPUname));

更新
为了防止以前的元素重复：

itemList = tempDistSPUI; 
List<DistributionStandardPackingUnitItems> itemListNew = new List<DistributionStandardPackingUnitItems>();
itemListNew = packBLL.getAllDistSPUItemByDistributionIDnSPUName(distributionID, SPUname);
// get all previous IDs in a List<int>
List<int> previousIDs = itemList.Select(x => x.id).ToList();
// filter itemListNew and add the elements to itemList
itemList.AddRange(itemListNew.Where(x => !previousIDs.Contains(x.id));