我有一个gridview MyGridView，它包含两个DropDownLists和一个TextBox。过程是，我从第一个DropDownList中选择一个项目，在第二个DropDown中填充与所选项目相关的项目。我在文本框中输入一些文本，然后按下＆＃34;添加＆＃34;在gridview的页脚中，创建一个新行。但第一行仍有数据。
我使用Dictionary填充DropDowns。在第一个下拉列表的SelectedIndexChanged事件中，为第二个下拉列表创建一个新字典。
当我点击添加按钮时，文本框数据会保留，但下拉列表中会出现这种情况。数据源丢失。
如何在以前的行中保留数据？
**编辑：请参阅代码。我在http://www.codeproject.com/Articles/467788/Dynamically-adding-and-deleting-rows-from-ASP-NET **
使用了教程代码：
GridView代码
<asp:GridView ID="SODetailsGrid" runat="server" ShowFooter="True"
AutoGenerateColumns="False" OnRowDeleting="SODetailsGrid_RowDeleting"
Width="97%" Style="text-align: left" ondatabound="SODetailsGrid_DataBound"
onrowdatabound="SODetailsGrid_RowDataBound">
<Columns>
<asp:BoundField DataField="RowNumber" HeaderStyle-CssClass="first-name"
HeaderText="SNo" Visible="false">
<HeaderStyle CssClass="first-name" />
</asp:BoundField>
<asp:TemplateField HeaderText="Category">
<ItemTemplate>
<asp:DropDownList ID="ddlCategory" AutoPostBack="true" CssClass="txt" runat="server" AppendDataBoundItems="true" onselectedindexchanged="ddlCategory_SelectedIndexChanged">
</asp:DropDownList>
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="ddlCategory"
ErrorMessage="*" SetFocusOnError="True"></asp:RequiredFieldValidator>
</ItemTemplate>
<FooterStyle HorizontalAlign="Center" />
<FooterTemplate>
<asp:Button ID="ButtonAdd" runat="server" CssClass="r_button" Text="Add New Item" onclick="ButtonAdd_Click" Width="120px" />
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Item">
<ItemTemplate>
<asp:DropDownList ID="ddlItem" AutoPostBack="true" CssClass="txt" runat="server" AppendDataBoundItems="true" onselectedindexchanged="ddlItem_SelectedIndexChanged">
</asp:DropDownList>
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ControlToValidate="ddlItem"
ErrorMessage="*" SetFocusOnError="True"></asp:RequiredFieldValidator>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Qty" HeaderStyle-CssClass="first-name">
<ItemTemplate>
<asp:TextBox ID="textQty" CssClass="txt" runat="server" AppendDataBoundItems="true">
</asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ControlToValidate="textQty"
ErrorMessage="*" SetFocusOnError="True"></asp:RequiredFieldValidator>
</ItemTemplate>
<HeaderStyle CssClass="first-name" />
</asp:TemplateField>
<asp:TemplateField HeaderText="Disc%" >
<ItemTemplate>
<asp:TextBox ID="textDiscount" CssClass="txt" runat="server" AppendDataBoundItems="true" >
</asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator4" runat="server" ControlToValidate="textDiscount"
ErrorMessage="*"></asp:RequiredFieldValidator>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Amount" HeaderStyle-CssClass="first-name">
<ItemTemplate>
<asp:TextBox ID="textAmount" CssClass="txt" runat="server" AppendDataBoundItems="true">
</asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator5" runat="server" ControlToValidate="textAmount"
ErrorMessage="*" ></asp:RequiredFieldValidator>
</ItemTemplate>
<HeaderStyle CssClass="first-name" />
</asp:TemplateField>
<asp:TemplateField HeaderText="Planned Delivery Date">
<ItemTemplate>
<asp:TextBox ID="textPDelivery" CssClass="txt" runat="server" AppendDataBoundItems="true">
</asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator7" runat="server" ControlToValidate="textPDelivery"
ErrorMessage="*" ></asp:RequiredFieldValidator>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Planned Shipment Date" >
<ItemTemplate>
<asp:TextBox ID="textPShipment" CssClass="txt" runat="server" AppendDataBoundItems="true">
</asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator8" runat="server" ControlToValidate="textPShipment"
ErrorMessage="*" ></asp:RequiredFieldValidator>
</ItemTemplate>
</asp:TemplateField>
<asp:CommandField ShowDeleteButton="True" />
</Columns>
</asp:GridView>
背后的代码：
public partial class newso : System.Web.UI.Page
{
DataTable dt;
public string itemurl = myur;
public string itemcaturl = mysecondurl;
public string uniturl = mythirdurl;
public string token;
public Dictionary<string, int> itemMap = new Dictionary<string, int>();
public Dictionary<int, string> itemDictionary;
public Dictionary<int, string> itemcatDictionary;
public DropDownList ddlItem;
public DropDownList ddlCategory;
protected void Page_Load(object sender, EventArgs e)
{
token = Session["token"].ToString();
if (!IsPostBack)
{
try
{
string itemcategory = GetJSON(itemcaturl);
bindItemCatNameDDL(itemcategory);
string units = GetJSON(uniturl);
bindUnitDDL(units);
}
catch (Exception ex)
{
}
}
FirstGridViewRow();
}
public string GetJSON(string myurl)
{
string formattedUri = String.Format(CultureInfo.InvariantCulture, myurl);
HttpWebRequest webRequest = GetWebRequest(formattedUri);
webRequest.ContentType = "application/json; charset=utf-8";
webRequest.Headers.Add("X-Token", token);
HttpWebResponse response = (HttpWebResponse)webRequest.GetResponse();
string jsonResponse = string.Empty;
using (StreamReader sr = new StreamReader(response.GetResponseStream()))
{
jsonResponse = sr.ReadToEnd();
}
return jsonResponse;
}
private HttpWebRequest GetWebRequest(string formattedUri)
{
// Create the request’s URI.
Uri serviceUri = new Uri(formattedUri, UriKind.Absolute);
// Return the HttpWebRequest.
return (HttpWebRequest)System.Net.WebRequest.Create(serviceUri);
}
public void bindItemNameDDL(string items, int cat, object sender)
{
itemDictionary = new Dictionary<int, string>();
string newitemjson = "{\"data\":" + items + "}";
itemDictionary.Add(0, "Select");
IList<Item> item = new JavaScriptSerializer().Deserialize<IList<Item>>(items);
GridViewRow gvr = (GridViewRow)(((Control)sender).NamingContainer);
ddlItem = (DropDownList)gvr.FindControl("ddlItem");
ddlItem.DataSource = item;
ddlItem.DataTextField = "Item_Name";
ddlItem.DataValueField = "RowNum";
ddlItem.DataBind();
}
public void bindItemCatNameDDL(string itemcats)
{
itemcatDictionary = new Dictionary<int, string>();
string newitemcatjson = "{\"data\":" + itemcats + "}";
itemcatDictionary.Add(0, "Select");
ItemCategory itemcatDetails = new System.Web.Script.Serialization.JavaScriptSerializer().Deserialize<ItemCategory>(newitemcatjson);
foreach (var item in itemcatDetails.data)
{
Console.WriteLine("id: {0}, name: {1}", item.RowNum, item.ItemCategory_Name);
itemcatDictionary.Add(item.RowNum, item.ItemCategory_Name);
}
ddlItem.DataSource = itemcatDictionary;
}
public void bindUnitDDL(string units)
{
Dictionary<int, string> unitDictionary = new Dictionary<int, string>();
string newunitjson = "{\"data\":" + units + "}";
Units unitDetails = new System.Web.Script.Serialization.JavaScriptSerializer().Deserialize<Units>(newunitjson);
foreach (var item in unitDetails.data)
{
Console.WriteLine("id: {0}, name: {1}", item.RowNum, item.Unit_Name);
unitDictionary.Add(item.RowNum, item.Unit_Name);
}
}
/*
* Fill data to dropdownlists
*/
protected void SODetailsGrid_DataBound(object sender, EventArgs e)
{
}
protected void SODetailsGrid_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
//Find the DropDownList in the Row
ddlCategory = (e.Row.FindControl("ddlCategory") as DropDownList);
ddlCategory.DataSource = itemcatDictionary;
ddlCategory.DataTextField = "Value";
ddlCategory.DataValueField = "Key";
ddlCategory.DataBind();
ddlItem = (e.Row.FindControl("ddlItem") as DropDownList);
}
}
protected void ddlCategory_SelectedIndexChanged(object sender, EventArgs e)
{
string items = GetJSON(itemurl);
GridViewRow gvr = (GridViewRow)(((Control)sender).NamingContainer);
ddlCategory = (DropDownList)gvr.FindControl("ddlCategory");
ddlItem = (DropDownList)gvr.FindControl("ddlItem");
bindItemNameDDL(items, Convert.ToInt32(ddlCategory.SelectedItem.Value),sender);
}
protected void ddlItem_SelectedIndexChanged(object sender, EventArgs e)
{
GridViewRow gvr = (GridViewRow)(((Control)sender).NamingContainer);
ddlItem = (DropDownList)gvr.FindControl("ddlItem");
}
protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
{
}
private void FirstGridViewRow()
{
DataTable dt = new DataTable();
DataRow dr = null;
dt.Columns.Add(new DataColumn("RowNumber", typeof(string)));
dt.Columns.Add(new DataColumn("Col1", typeof(string)));
dt.Columns.Add(new DataColumn("Col2", typeof(string)));
dt.Columns.Add(new DataColumn("Col3", typeof(string)));
dt.Columns.Add(new DataColumn("Col4", typeof(string)));
dt.Columns.Add(new DataColumn("Col5", typeof(string)));
dt.Columns.Add(new DataColumn("Col6", typeof(string)));
dt.Columns.Add(new DataColumn("Col7", typeof(string)));
dr = dt.NewRow();
dr["RowNumber"] = 1;
dr["Col1"] = string.Empty;
dr["Col2"] = string.Empty;
dr["Col3"] = string.Empty;
dr["Col4"] = string.Empty;
dr["Col5"] = string.Empty;
dr["Col6"] = string.Empty;
dr["Col7"] = string.Empty;
dt.Rows.Add(dr);
ViewState["CurrentTable"] = dt;
SODetailsGrid.DataSource = dt;
SODetailsGrid.DataBind();
Button btnAdd = (Button)SODetailsGrid.FooterRow.Cells[6].FindControl("ButtonAdd");
//Page.Form.DefaultFocus = btnAdd.ClientID;
}
private void AddNewRow()
{
int rowIndex = 0;
if (ViewState["CurrentTable"] != null)
{
DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"];
DataRow drCurrentRow = null;
if (dtCurrentTable.Rows.Count > 0)
{
for (int i = 1; i <= dtCurrentTable.Rows.Count; i++)
{
DropDownList ddlCategory = (DropDownList)SODetailsGrid.Rows[rowIndex].Cells[1].FindControl("ddlCategory");
DropDownList ddlItem = (DropDownList)SODetailsGrid.Rows[rowIndex].Cells[2].FindControl("ddlItem");
TextBox textQty = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[3].FindControl("textQty");
TextBox textDiscount = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[4].FindControl("textDiscount");
TextBox textAmount = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[5].FindControl("textAmount");
TextBox textPDelivery = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[6].FindControl("textPDelivery");
TextBox textPShipment = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[7].FindControl("textPShipment");
drCurrentRow = dtCurrentTable.NewRow();
drCurrentRow["RowNumber"] = i + 1;
dtCurrentTable.Rows[i - 1]["Col1"] = ddlCategory.SelectedValue;
dtCurrentTable.Rows[i - 1]["Col2"] = ddlItem.SelectedValue;
dtCurrentTable.Rows[i - 1]["Col3"] = textQty.Text;
dtCurrentTable.Rows[i - 1]["Col4"] = textDiscount.Text;
dtCurrentTable.Rows[i - 1]["Col5"] = textAmount.Text;
dtCurrentTable.Rows[i - 1]["Col6"] = textPDelivery.Text;
dtCurrentTable.Rows[i - 1]["Col7"] = textPShipment.Text;
rowIndex++;
}
dtCurrentTable.Rows.Add(drCurrentRow);
ViewState["CurrentTable"] = dtCurrentTable;
DebugTable(dtCurrentTable);
SODetailsGrid.DataSource = dtCurrentTable;
SODetailsGrid.DataBind();
DropDownList ddlcat = (DropDownList)SODetailsGrid.Rows[1].Cells[1].FindControl("ddlCategory");
ddlcat.Focus();
// txn.Focus;
}
}
else
{
Response.Write("ViewState is null");
}
SetPreviousData();
}
private void SetPreviousData()
{
int rowIndex = 0;
if (ViewState["CurrentTable"] != null)
{
DataTable dt = (DataTable)ViewState["CurrentTable"];
if (dt.Rows.Count > 0)
{
for (int i = 0; i < dt.Rows.Count; i++)
{
DropDownList ddlCategory = (DropDownList)SODetailsGrid.Rows[rowIndex].Cells[1].FindControl("ddlCategory");
DropDownList ddlItem = (DropDownList)SODetailsGrid.Rows[rowIndex].Cells[2].FindControl("ddlItem");
TextBox textQty = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[3].FindControl("textQty");
TextBox textDiscount = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[4].FindControl("textDiscount");
TextBox textAmount = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[5].FindControl("textAmount");
TextBox textPDelivery = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[6].FindControl("textPDelivery");
TextBox textPShipment = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[7].FindControl("textPShipment");
ddlCategory.SelectedValue = dt.Rows[i]["Col1"].ToString();
ddlItem.SelectedValue = dt.Rows[i]["Col2"].ToString();
textQty.Text = dt.Rows[i]["Col3"].ToString();
textDiscount.Text = dt.Rows[i]["Col4"].ToString();
textAmount.Text = dt.Rows[i]["Col5"].ToString();
textPDelivery.Text = dt.Rows[i]["Col6"].ToString();
textPShipment.Text = dt.Rows[i]["Col7"].ToString();
rowIndex++;
}
}
}
}
protected void ButtonAdd_Click(object sender, EventArgs e)
{
AddNewRow();
}
protected void SODetailsGrid_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
SetRowData();
if (ViewState["CurrentTable"] != null)
{
DataTable dt = (DataTable)ViewState["CurrentTable"];
DataRow drCurrentRow = null;
int rowIndex = Convert.ToInt32(e.RowIndex);
if (dt.Rows.Count > 1)
{
dt.Rows.Remove(dt.Rows[rowIndex]);
drCurrentRow = dt.NewRow();
ViewState["CurrentTable"] = dt;
SODetailsGrid.DataSource = dt;
SODetailsGrid.DataBind();
for (int i = 0; i < SODetailsGrid.Rows.Count - 1; i++)
{
SODetailsGrid.Rows[i].Cells[0].Text = Convert.ToString(i + 1);
}
SetPreviousData();
}
}
}
private void SetRowData()
{
int rowIndex = 0;
if (ViewState["CurrentTable"] != null)
{
DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"];
DataRow drCurrentRow = null;
if (dtCurrentTable.Rows.Count > 0)
{
for (int i = 1; i <= dtCurrentTable.Rows.Count; i++)
{
DropDownList ddlCategory = (DropDownList)SODetailsGrid.Rows[rowIndex].Cells[1].FindControl("ddlCategory");
DropDownList ddlItem = (DropDownList)SODetailsGrid.Rows[rowIndex].Cells[2].FindControl("ddlItem");
TextBox textQty = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[3].FindControl("textQty");
TextBox textDiscount = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[4].FindControl("textDiscount");
TextBox textAmount = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[5].FindControl("textAmount");
TextBox textPDelivery = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[6].FindControl("textPDelivery");
TextBox textPShipment = (TextBox)SODetailsGrid.Rows[rowIndex].Cells[7].FindControl("textPShipment");
drCurrentRow = dtCurrentTable.NewRow();
drCurrentRow["RowNumber"] = i + 1;
dtCurrentTable.Rows[i - 1]["Col1"] = ddlCategory.SelectedValue;
dtCurrentTable.Rows[i - 1]["Col2"] = ddlItem.SelectedValue;
dtCurrentTable.Rows[i - 1]["Col3"] = textQty.Text;
dtCurrentTable.Rows[i - 1]["Col4"] = textDiscount.Text;
dtCurrentTable.Rows[i - 1]["Col5"] = textAmount.Text;
dtCurrentTable.Rows[i - 1]["Col6"] = textPDelivery.Text;
dtCurrentTable.Rows[i - 1]["Col7"] = textPShipment.Text;
rowIndex++;
}
ViewState["CurrentTable"] = dtCurrentTable;
}
}
else
{
Response.Write("ViewState is null");
}
//SetPreviousData();
}
protected void btnSave_Click(object sender, EventArgs e)
{
try
{
SetRowData();
DataTable table = ViewState["CurrentTable"] as DataTable;
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
}
}