如何从asp.net的下拉列表中动态添加不同的控件 [英] How do I add different controls dynamically on selection from dropdown list in asp.net
问题描述
你好
我在asp.net网站上创建一个页面，我在下拉列表中动态添加控件，但是从每个选项中下拉列表由于下拉列表的回发而丢失了之前的控件。
我想在下拉列表中选择的面板中动态添加控件。例如：如果我从下拉列表中选择文本框，则应该将控件添加到面板然后再次从下拉列表中选择按钮，该按钮应添加到面板中。现在面板应该有文本框和按钮。现在如果我从下拉列表中选择下拉列表，它应该被添加到面板，即面板应该显示文本框，按钮和下拉列表。
任何人都可以建议我或者帮我解决一下。
谢谢和问候
< blockquote>现在更新的代码如下：
protected void ddlIds_SelectedIndexChanged（object sender，EventArgs e）
{
switch（ddlIds.SelectedItem.Text）
{
caseTextbox：
var txtBox = string.Empty;
if（hdnValue.Value！=&& hdnValue.Value.Contains（txtBox））
{
var value = hdnValue.Value.Split（'^'） ;
int latestID = CountStringOccurrences（hdnValue.Value，txtBox）+ 1;
txtBox =txtBox+ latestID.ToString（）;
hdnValue.Value = hdnValue.Value +^+ txtBox;
}
其他
{
txtBox =txtBox1;
hdnValue.Value = hdnValue.Value +^+ txtBox;
}
休息;
caseCheckBox：
var chkbox = string.Empty;
if（hdnValue.Value！=&& hdnValue.Value.Contains（chkBox））
{
var value = hdnValue.Value.Split（'^'） ;
int latestID = CountStringOccurrences（hdnValue.Value，chkBox）+ 1;
chkbox =chkBox+ latestID.ToString（）;
hdnValue.Value = hdnValue.Value +^+ chkbox;
}
else
{
chkbox =chkBox1;
hdnValue.Value = hdnValue.Value +^+ chkbox;
}
休息;
}
if（hdnValue.Value！=）
{
var val = hdnValue.Value.Split（'^'）;
foreach（val中的var ID）
{
if（IDs.Contains（chk））
{
CheckBox chkBox = new CheckBox（）;
chkBox.ID = IDs;
Panel1.Controls.Add（chkBox）;
}
else if（IDs.Contains（txt））
{
TextBox TxtBox = new TextBox（）;
TxtBox.ID = ID;
Panel1.Controls.Add（TxtBox）;
}
}
}
}
在回帖中处理控件
这个函数我用过链接ttp：//www.dotnetperls.com/string-occurrence
public static int CountStringOccurrences（string text，string pattern）
{
int count = 0;
int i = 0;
while（（i = text.IndexOf（pattern，i））！= -1）
{
i + = pattern.Length;
count ++;
}
返回计数;
}
如果你愿意，可以将它标记为解决方案
假设你有DDL as -
< asp：DropDownList ID = ddlSample runat = server AutoPostBack = True OnSelectedIndexChanged = ddlSample_SelectedIndexChanged >
< asp：ListItem > 文本框< / asp：ListItem >
< asp：ListItem < span class =code-keyword>> 按钮< / asp：ListItem >
< asp：ListItem > ComboBox < / asp：ListItem >
< asp：ListItem > DropdownList < / asp：ListItem >
< span class =code-keyword>< / asp：DropDownList >
受保护 void ddlSample_SelectedIndexChanged（ object sender，EventArgs e）
{
if （ddlSample.SelectedItem.Text == Textbox）
{
TextBox TxtBoxU = new TextBox（）;
TxtBoxU.ID = TextBoxU + i.ToString（）;
// 将文本框添加到Panel。
Panel1.Controls.Add （TxtBoxU）;
}
}
请参考：
http：// www。 dotnettips4u.com/2013/03/dynamically-creating-text-boxes-using-c.html [ ^ ]
Yash，
你可以使用技巧，我为你提供样品你可以添加你的逻辑
在Aspx中使用：
< asp：DropDownList ID = ddlIds runat = 服务器 AutoPostBack = True OnSelectedIndexChanged = ddlIds_SelectedIndexChanged >
< asp：ListItem > 文本框< / asp：ListItem >
< asp：ListItem > 按钮< / asp：ListItem >
< asp：ListItem > CheckBox < / asp：ListItem >
< asp：ListItem > DropdownList < / asp：ListItem >
< / asp：DropDownList >
< asp：Panel ID = Panel1 runat= 服务器 > < / asp：Panel >
< asp：HiddenField ID = hdnValue runat = 服务器 / >
在代码背后使用此逻辑
protected void ddlIds_SelectedIndexChanged（object sender，EventArgs e）
{
TextBox TxtBox = new TextBox（）;
CheckBox chkBox = new CheckBox（）;
switch（ddlIds.SelectedItem.Text）
{
caseTextbox：
TxtBox.ID =txtBox;
hdnValue.Value = hdnValue.Value +^+ TxtBox.ID;
休息;
caseCheckBox：
chkBox.ID =chkBox;
hdnValue.Value = hdnValue.Value +^+ chkBox.ID;
休息;
}
if（hdnValue.Value！=）
{
var val = hdnValue.Value.Split（'^'）;
foreach（val中的var ID）
{
if（IDs.Contains（chk））
{
chkBox.ID = IDs;
Panel1.Controls.Add（chkBox）;
}
否则if（IDs.Contains（txt））
{
TxtBox.ID = IDs;
Panel1.Controls.Add（TxtBox）;
}
}
}
}
希望这会如果这是解决方案，请为您做好，请将其标记为解决方案
Hello
I am creating a page in asp.net website on which i add the controls dynamically on selection from drop down list, but on every selection from the drop down list the previous control lost due to post back of drop down list.
I want to add the controls dynamically in my panel on selection from drop down list. For example: if i select the text box from the drop down list,the control should be add to the panel then again if i select the button from drop down list, the button should be added to the panel. Now the panel should have the text box and button. Now if i select the drop down list from the drop down list, it should be added to the panel i.e panel should display the text box ,button and drop down list in it.
Can any body suggest me or help me to figure it out.
Thanks & Regards
Now Updated code is this :
protected void ddlIds_SelectedIndexChanged(object sender, EventArgs e) { switch (ddlIds.SelectedItem.Text) { case "Textbox": var txtBox = string.Empty; if (hdnValue.Value != "" && hdnValue.Value.Contains("txtBox")) { var value = hdnValue.Value.Split('^'); int latestID = CountStringOccurrences(hdnValue.Value, "txtBox") + 1; txtBox = "txtBox" + latestID.ToString(); hdnValue.Value = hdnValue.Value + "^" + txtBox; } else { txtBox = "txtBox1"; hdnValue.Value = hdnValue.Value + "^" + txtBox; } break; case "CheckBox": var chkbox = string.Empty; if (hdnValue.Value != "" && hdnValue.Value.Contains("chkBox")) { var value = hdnValue.Value.Split('^'); int latestID = CountStringOccurrences(hdnValue.Value, "chkBox") + 1; chkbox = "chkBox" + latestID.ToString(); hdnValue.Value = hdnValue.Value + "^" + chkbox; } else { chkbox = "chkBox1"; hdnValue.Value = hdnValue.Value + "^" + chkbox; } break; } if (hdnValue.Value != "") { var val = hdnValue.Value.Split('^'); foreach (var IDs in val) { if (IDs.Contains("chk")) { CheckBox chkBox = new CheckBox(); chkBox.ID = IDs; Panel1.Controls.Add(chkBox); } else if (IDs.Contains("txt")) { TextBox TxtBox = new TextBox(); TxtBox.ID = IDs; Panel1.Controls.Add(TxtBox); } } } }
Handle the control in post back
This function I have used from link ttp://www.dotnetperls.com/string-occurrence
public static int CountStringOccurrences(string text, string pattern) { int count = 0; int i = 0; while ((i = text.IndexOf(pattern, i)) != -1) { i += pattern.Length; count++; } return count; }
Marked it as solution if you like it
Suppose you have DDL as -
<asp:DropDownList ID="ddlSample" runat="server" AutoPostBack="True" OnSelectedIndexChanged="ddlSample_SelectedIndexChanged" > <asp:ListItem>Textbox</asp:ListItem> <asp:ListItem>Button</asp:ListItem> <asp:ListItem>ComboBox</asp:ListItem> <asp:ListItem>DropdownList</asp:ListItem> </asp:DropDownList>
protected void ddlSample_SelectedIndexChanged(object sender, EventArgs e) { if (ddlSample.SelectedItem.Text == "Textbox") { TextBox TxtBoxU = new TextBox(); TxtBoxU.ID = "TextBoxU" + i.ToString(); //Add the textbox to the Panel. Panel1.Controls.Add(TxtBoxU); } }
refer this :
http://www.dotnettips4u.com/2013/03/dynamically-creating-text-boxes-using-c.html[^]
Yash ,
you can use a trick, I am providing you a sample You can add your logic
In Aspx Use :
<asp:DropDownList ID="ddlIds" runat="server" AutoPostBack="True" OnSelectedIndexChanged="ddlIds_SelectedIndexChanged" > <asp:ListItem>Textbox</asp:ListItem> <asp:ListItem>Button</asp:ListItem> <asp:ListItem>CheckBox</asp:ListItem> <asp:ListItem>DropdownList</asp:ListItem> </asp:DropDownList> <asp:Panel ID="Panel1" runat="server"></asp:Panel> <asp:HiddenField ID="hdnValue" runat="server"/>
In code behind use this logic
protected void ddlIds_SelectedIndexChanged(object sender, EventArgs e) { TextBox TxtBox = new TextBox(); CheckBox chkBox = new CheckBox(); switch (ddlIds.SelectedItem.Text) { case "Textbox": TxtBox.ID = "txtBox"; hdnValue.Value = hdnValue.Value + "^" + TxtBox.ID; break; case "CheckBox": chkBox.ID = "chkBox"; hdnValue.Value = hdnValue.Value + "^" + chkBox.ID; break; } if (hdnValue.Value != "") { var val = hdnValue.Value.Split('^'); foreach (var IDs in val) { if (IDs.Contains("chk")) { chkBox.ID = IDs; Panel1.Controls.Add(chkBox); } else if (IDs.Contains("txt")) { TxtBox.ID = IDs; Panel1.Controls.Add(TxtBox); } } } }
Hope this will do for you if that is the solution please mark it as solution
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