C# 单击按钮时动态添加新文本框
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Dynamically add a new text box when clicking a button
提问by rohan panchal
I'm using this code
我正在使用此代码
<asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
<asp:Button ID="addnewtext" runat="server" Text="Add" onclick="addnewtext_Click" width="76px" />
and aspx.cspage code:
和aspx.cs页面代码：
TextBox tb;
static int i = 0;
protected void addnewtext_Click(object sender, EventArgs e)
{
tb = new TextBox();
tb.ID = i.ToString();
PlaceHolder1.Controls.Add(tb);
i++;
}
On every click on the button I want to add another text box.
每次单击按钮时，我都想添加另一个文本框。
采纳答案by Pranay Rana
Reason:When you click button again than it do postback to serverside and it removes previously added dynamically textbox
原因：当您再次单击按钮而不是回发到服务器端时，它会删除以前添加的动态文本框
Solution:To add it again you need to do like this
解决方案：要再次添加它，您需要这样做
TextBox tb;
static int i = 0;
protected void addnewtext_Click(object sender, EventArgs e)
{
i++;
for(j=0;j<=i;j++)
{
tb = new TextBox();
tb.ID = j.ToString();
PlaceHolder1.Controls.Add(tb);
}
}
that means you need to create the added textbox again...because you are adding control dynamically to the page...
这意味着您需要再次创建添加的文本框...因为您正在向页面动态添加控件...
Article like this might help you : Retaining State for Dynamically Created Controls in ASP.NET applications
像这样的文章可能对您有所帮助：在 ASP.NET 应用程序中为动态创建的控件保留状态
回答by sajanyamaha
Lets go with a list view
让我们使用列表视图
<asp:ListView ID="lvDynamicTextboxes" runat="server"
ItemPlaceholderID="itemPlaceholder"> <LayoutTemplate> <table> <asp:PlaceHolder ID="itemPlaceholder"
runat="server"></asp:PlaceHolder> </table> </LayoutTemplate> <ItemTemplate> <tr> <asp:TextBox ID="txtText" runat="server"> </asp:TextBox> </tr> </ItemTemplate>
</asp:ListView>
<asp:Button ID="btnAddTextBox" runat="server"
Text="Add" onclick="btnAddTextBox_Click" />
And some codes
还有一些代码
private void BindListView()
{
//get the current textbox count int count = 1;
if (ViewState["textboxCount"] != null)
count = (int)ViewState["textboxCount"];
//create an enumerable range based on the current count IEnumerable<int> enumerable = Enumerable.Range(1, count);
//bind the listview this.lvDynamicTextboxes.DataSource = enumerable;
this.lvDynamicTextboxes.DataBind();
}
private void IncrementTextboxCount()
{
int count = 1;
if (ViewState["textboxCount"] != null)
count = (int)ViewState["textboxCount"];
count++;
ViewState["textboxCount"] = count;
}
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
this.BindListView();
}
}
protected void btnAddTextBox_Click(object sender, EventArgs e)
{
this.IncrementTextboxCount();
this.BindListView();
}
Now To extract valuesfrom these added textboxes :
现在要从这些添加的文本框中提取值：
private IList<string> GetValues()
{
List<string> values = new List<string>();
TextBox txt = null;
foreach (ListViewItem item in this.lvDynamicTextboxes.Items)
{
if (item is ListViewDataItem)
{
txt = (TextBox)item.FindControl("txtText");
values.Add(txt.Text);
}
}
return values;
}
