Introduction: In this article I am going to explain How to find
all asp.net controls of specific type placed on the web page/form. I have
created an example of finding all of the control by their type and clearing or resetting their
values.
In previous articles i explained How to read and write text file in asp.net c#, vb and Asp.net server side yes no confirmation box using jquery and Bootstrap modal dialog popup example in asp.net and Check uncheck all checkboxes in gridview using jquery and Jquery to validate file type and size before uploading through asp.net fileupload control
Description: While working on page
it may be required to perform an action based on the type of the control. Finding
all controls present on the page and clearing or resetting their values was
required in my case. Here I have provided
an example how I achieved that.
Implementation: Let’s create a page and place checkbox, checkboxlist, textbox, dropdownlist, radiobutton, radiobuttonlist, label and hiddenfield controls etc.
HTML Source
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<fieldset style="width: 300px">
<legend>Reset CheckBox</legend>
<asp:CheckBox ID="CheckBox1" runat="server" Text="Checkbox1" />
<asp:CheckBox ID="CheckBox2" runat="server" Text="Checkbox2" />
</fieldset>
<fieldset style="width: 300px">
<legend>Reset CheckBoxList</legend>
<asp:CheckBoxList ID="CheckBoxList1" runat="server" RepeatColumns="4" RepeatDirection="Horizontal">
<asp:ListItem>Item1</asp:ListItem>
<asp:ListItem>Item2 </asp:ListItem>
<asp:ListItem>Item3 </asp:ListItem>
<asp:ListItem>Item4 </asp:ListItem>
</asp:CheckBoxList>
</fieldset>
<fieldset style="width: 300px">
<legend>Clear TextBox</legend>
<asp:TextBox ID="TextBox1" runat="server" Width="140px"></asp:TextBox>
<asp:TextBox ID="TextBox2" runat="server" Width="140px"></asp:TextBox>
</fieldset>
<fieldset style="width: 300px">
<legend>Reset DropDownList</legend>
<asp:DropDownList ID="DropDownList1" runat="server">
<asp:ListItem>-- Select --</asp:ListItem>
<asp:ListItem>Item1</asp:ListItem>
<asp:ListItem>Item2 </asp:ListItem>
<asp:ListItem>Item3 </asp:ListItem>
<asp:ListItem>Item4 </asp:ListItem>
</asp:DropDownList>
</fieldset>
<fieldset style="width: 300px">
<legend>Reset RadioButton</legend>
<asp:RadioButton ID="RadioButton1" runat="server" Text="Radiobutton" />
</fieldset>
<fieldset style="width: 300px">
<legend>Reset RadioButtonList</legend>
<asp:RadioButtonList ID="RadioButtonList1" runat="server" RepeatColumns="4" RepeatDirection="Horizontal">
<asp:ListItem>Item1</asp:ListItem>
<asp:ListItem>Item2</asp:ListItem>
<asp:ListItem>Item3</asp:ListItem>
<asp:ListItem>Item4</asp:ListItem>
</asp:RadioButtonList>
</fieldset>
<fieldset style="width: 300px">
<legend>Reset Label Text</legend>
<asp:Label ID="Label1" runat="server" Text="label1
text"></asp:Label>  
<asp:Label ID="Label2" runat="server" Text="label2
text"></asp:Label>
</fieldset>
<asp:HiddenField ID="HiddenField1" runat="server" Value="123" />
<br />
<asp:Button ID="btnReset" runat="server"
Text="Reset controls" OnClick="btnReset_Click" />
</div>
</form>
</body>
</html>
Asp.Net C# Code to find controls by their type and clear
values
protected void btnReset_Click(object sender, EventArgs e)
{
//Loop through all the
control present on the web page/form
foreach (Control ctrl in form1.Controls)
{
//check
for all TextBox controls on the page and clear them
if (ctrl is TextBox)// or if
(ctrl.GetType().Equals(typeof(TextBox)))
{
((TextBox)(ctrl)).Text = string.Empty;
}
//check
for all Label controls on the page and clear them
else if (ctrl is Label) // or else if
(ctrl.GetType().Equals(typeof(Label)))
{
((Label)(ctrl)).Text = string.Empty;
}
//check
for all DropDownList controls on the page and reset them
else if (ctrl is DropDownList)// or else if
(ctrl.GetType().Equals(typeof(DropDownList)))
{
((DropDownList)(ctrl)).ClearSelection();
}
//check
for all CheckBox controls on the page and unchecked the selection
else if (ctrl is CheckBox) // or else if
(ctrl.GetType().Equals(typeof(CheckBox)))
{
((CheckBox)(ctrl)).Checked = false;
}
//check
for all CheckBoxList controls on the page and unchecked all the selections
else if (ctrl is CheckBoxList) // or else if
(ctrl.GetType().Equals(typeof(CheckBoxList)))
{
((CheckBoxList)(ctrl)).ClearSelection();
}
//check
for all RadioButton controls on the page and unchecked the selection
else if (ctrl is RadioButton) // or else if
(ctrl.GetType().Equals(typeof(RadioButton)))
{
((RadioButton)(ctrl)).Checked = false;
}
//check
for all RadioButtonList controls on the page and unchecked the selection
else if (ctrl is RadioButtonList) // or else if
(ctrl.GetType().Equals(typeof(RadioButtonList)))
{
((RadioButtonList)(ctrl)).ClearSelection();
}
//check
for all hiddenfield controls on the page and clear them
else if (ctrl is HiddenField) //or else if
(ctrl.GetType().Equals(typeof(HiddenField)))
{
((HiddenField)(ctrl)).Value = string.Empty;
}
}
}
Asp.Net VB Code to find controls by their type and clear
values
Protected Sub btnReset_Click(sender As Object, e As EventArgs) Handles btnReset.Click
'Loop through all the control
present on the web page/form
For Each ctrl As Control In form1.Controls
'check
for all TextBox controls on the page and clear them
If TypeOf ctrl Is TextBox Then
DirectCast(ctrl, TextBox).Text = String.Empty
'check
for all Label controls on the page and clear them
ElseIf TypeOf ctrl Is Label Then
DirectCast(ctrl, Label).Text = String.Empty
'check
for all DropDownList controls on the page and reset them
ElseIf TypeOf ctrl Is DropDownList Then
DirectCast(ctrl, DropDownList).ClearSelection()
'check
for all CheckBox controls on the page and unchecked the selection
ElseIf TypeOf ctrl Is CheckBox Then
DirectCast(ctrl, CheckBox).Checked = False
'check
for all CheckBoxList controls on the page and unchecked all the selections
ElseIf TypeOf ctrl Is CheckBoxList Then
DirectCast(ctrl, CheckBoxList).ClearSelection()
'check
for all RadioButton controls on the page and unchecked the selection
ElseIf TypeOf ctrl Is RadioButton Then
DirectCast(ctrl, RadioButton).Checked = False
'check
for all RadioButtonList controls on the page and unchecked the selection
ElseIf TypeOf ctrl Is RadioButtonList Then
DirectCast(ctrl, RadioButtonList).ClearSelection()
'check
for all hiddenfield controls on the page and clear them
ElseIf TypeOf ctrl Is HiddenField Then
DirectCast(ctrl, HiddenField).Value = String.Empty
End If
Next
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