In one of my web page, there are 12 checkbox controls in a div tag. I want to make sure the user check at least one checkbox in a div after they submit the form.in one of my asp.net web page. Any idea? I mean server side. I have done client side, but as you know, no one could guarantee all client browser enable javascript.
Since you're using ASP.Net, you may want to consider using the
<asp:CheckboxList />
control, and add an <asp:CustomValidator> plus validation functions that ensure one checkbox was checked.
While I agree with what others said about the validators, this code does what you want:
int i = 0;
foreach (Control ctl in myForm.FindControl("myDiv").Controls)
{
if (ctl is CheckBox)
{
if (((CheckBox)ctl).Checked)
i++;
}
}
Can you use JQuery? If so, check this out:
Get a list of checked checkboxes in a div using jQuery
Does it have to be is C#? Sounds a lot simplier if you just did it in javascript.
You want to look at the OnClientClick property of the asp:CheckBox control.
Here is an example:
<asp:CheckBox runat="server" OnClientClick="alert(this.checked);" />
In your javascript code (called by the handler) you can loop through all children of the div, looking for checkbox type inputs. jQuery is best for that. You could use something like this:
function countChecked() {
return $("input:checked").length;
}
That function above will return the number of checked checkboxes. After that it's trivial to validate your form. Just remember to return false from the handler called by OnClientClick to avoid a postback (in the event your form doesn't validate).
I just realized you edited your question while I was typing an answer. The above is a client side solution only.
If you just want a server side check for this and dont mind autopostback, give this a try. Just set an event handler for the SelectedIndexChanged event and check to see if an option is selected there. You can then display an error of your choice.
Here is the checkboxlist code:
<asp:CheckBoxList ID="chkBxList" runat="server" AutoPostBack="true"
onselectedindexchanged="chkBxList_SelectedIndexChanged">
<asp:ListItem>option1</asp:ListItem>
<asp:ListItem>option2</asp:ListItem>
<asp:ListItem>option3</asp:ListItem>
</asp:CheckBoxList>
<asp:Label id="lblError" runat="server"></asp:Label>
Codebehind:
protected void chkBxList_SelectedIndexChanged(object sender, EventArgs e)
{
bool oneSelected = false;
foreach (ListItem item in chkBxList.Items)
{
if (item.Selected)
oneSelected = true;
}
if (!oneSelected)
lblError.Text = "Please select an option from the checkbox list.";
else
lblError.Text = "At least one checkbox is selected";
}
Even if the client disables JS this will still make sure they choose at least one.
Related
I have a bunch of LinkButtons on an asp.net page and need to set the visibility property of all the other LinkButtons on the page that have the same onclick attribute. I'm looking for a server side solution.
In the click handler I've gotten as far as listing the LinkButtons on the Page recursively but am stumped at how to tell if each LinkButton I find does or doesn't have a matching click handler.
The EventHandler property doesn't seem to contain any good info...
What is the best way to approach this?
You can give your linkbuttons a custom atttribute (for simplicity it can be the same as event handler name) e.g.
<asp:LinkButton ID="LinkButton1" runat="server" OnClick="LinkButton_Click" tag="LinkButton_Click">LinkButton1</asp:LinkButton>
<asp:LinkButton ID="LinkButton2" runat="server" OnClick="LinkButton_Click" tag="LinkButton_Click">LinkButton2</asp:LinkButton>
Then in your server-side code you can simple compare the attributes
protected void LinkButton_Click(object sender, EventArgs e)
{
// your recursive code retrieving current linkbutton
// ...
if ((sender as LinkButton).Attributes["tag"] == currentLinkbutton.Attributes["tag"])
{
// do your magic
}
}
An ugly solution would be to give all of those buttons the same CommandName attribute. Then you can just search for all link buttons with that attribute. Otherwise I am not sure that there is a great way to track the event handler used by each LinkButton.
Did you try linkbtn.Attributes["OnClick"]
Im trying to have my drop down list make four controls visible on the selectedindexchanged event for the control.
Basically when the user chooses "Server" from the drop down list the event should fire and the user should see two extra options.
Tried a tonne of approaches so far including text_changed event but nothing.
Here is what i got so far
//adds new fields to the form when the user selects server as the asset type
protected void AddNewFields(object sender, EventArgs e)
{
//If the asset is a server then make the extra controls available
if (TypeDDL.Text.Equals("Server"))
{
DNLabel.Visible.Equals(true);
//DNLabel.Visible = true;
DomainNameTB.Visible = true;
RoleLabel.Visible = true;
RoleDDL.Visible = true;
}
}
<asp:DropDownList ID="TypeDDL" runat="server" DataSourceID="AssetTypeDS"
DataTextField="AssetTypeDescription" DataValueField="AssetTypeID" OnTextChanged="AddNewFields">
</asp:DropDownList>
Add AutoPostback="True" to your DropDownList and the above code should trigger
As for an explanation: The drop down list doesn't automatically post back to the server. Changing a selection happens on the client side. Once you add the above, it'll repost the page. If you don't want the whole page to flicker each time someone changes a selection, you can either use some client side Javascript or Jquery, or use an asp:UpdatePanel
Please set AutoPostBack="True" property of a DropdownList...
add AutoPostBack="true" in dropdown
<asp:DropDownList ID="TypeDDL" runat="server" DataSourceID="AssetTypeDS" AutoPostBack="true"
DataTextField="AssetTypeDescription" DataValueField="AssetTypeID" OnTextChanged="AddNewFields">
</asp:DropDownList>
I have a list of asp:LinkLabels which are contained a repeater.
I have a button that says "Get Started" when a user clicks on this button, I want it to execute the first item in the repeater.
I have this code working fine in Chrome, but not in any other browser:
<asp:Button ID="SubmitInfo" runat="server" Text="Save and Get Started" Width="218px" OnClientClick="__doPostBack('rptList$ctl01$Label15','')" CssClass="submit-button-huge" OnClick="SubmitInfo_Click" />
Is there a way to do this server side without using the __doPostBack javascript?
Is there anything glaringly wrong here?
Difficult to answer without your whole code. I'll assume your LinkLabels are LinkButtons named "lb1", and you use commandName and CommandArgument, Repeater_ItemCommand
I would try something like this in the repeater.ItemCreated
private void Repeater_ItemCreated(object sender, System.Web.UI.WebControls.RepeaterItemEventArgs e)
{
if(e.Item.ItemType==ListItemType.Item || e.Item.ItemType==ListItemType.AlternatingItem)
{
var lb = (LinkButton)e.Item.FindControl("lb1");
if(IsPostBack && e.Item.ItemIndex==0)
{
SubmitInfo.Click+= (source,args)=>Repeater_ItemCommand(lb,new RepeaterCommandEventArgs(e.Item,lb,new CommandEventArgs(lb.CommandName,lb.CommandArgument)));
}
...
Hope this will help
Here is a part of my ASP.NET page.
<asp:DropDownList ID="DropDownList1" runat="server"
OnChange="return ListChange(this.value)"
onselectedindexchanged="DropDownList1_SelectedIndexChanged1"
AutoPostBack="True" >
<asp:ListItem Selected="True">Today</asp:ListItem>
<asp:ListItem>Yesterday</asp:ListItem>
<asp:ListItem Value="1">Specific Day</asp:ListItem>
<asp:ListItem>All Time</asp:ListItem>
</asp:DropDownList>
<asp:TextBox ID="txtDate" runat="server"></asp:TextBox>
Here is the Javascript.
function ListChange(txtVal) {
if (txtVal != 1 ) {
document.getElementById("txtDate").setAttribute("style", "visibility:hidden;");
return true;
}
else {
document.getElementById("txtDate").setAttribute("style", "visibility:visible;");
return false;
}
}
Here the objective is to show certain data according to the option selected by the user. In the Specific Day option, a textbox is shown to the user to insert date through javascript. But the onselectedindexchanged event is also raised which calls to server. I want to stop the event when "specific day" option is selected, but run when other options selected.
The code on OnChange="return ListChange(this.value)" is not stopping the event as used to when using a form with button.
It is one of the options that you can use.
Remove the selected index change event from markup.
on change event , check whether your validation has ran correctly.
if they have run make ajax request and do your stuff.
you do not need to call two separate functions simultaneously. Here is some jquery code that will do the trick in just a few lines.
$(document).ready(function(){
$('#DropDownList1').change(fnction(){
if($(this).text() != 'Specific Day') {
document.getElementById("txtDate").setAttribute("style", "visibility:hidden;");
return true;
} else {
document.getElementById("txtDate").setAttribute("style", "visibility:visible;");
return false;
}
});
});
By default ASP.Net will post back if you give AutoPostBack =true.
It is not considering return values.
Below is the code rendered at execution time. it uses settimeout and executed _doPostBack for submitting Form
onchange="return ListChange(this);setTimeout('__doPostBack(\'ctl00$MainContent$DropDownList1\',\'\')', 0)"
We need to think about stopping a form submit by setting a flag like Page_IsValid=false;
I would suggest that you do the show & hide using the .net code.
For example in VB.net
Put the following code in the DropDownList1_SelectedIndexChanged1 sub.
If DropDownList1.SelectedValue = "1" Then
txtDate.Visible = True
Else
txtDate.Visible = False
End If
Rather than have 3 different on click/change events.
Then remove the JS and the on change and on client click events, just leave it with onselectedindexchanged="DropDownList1_SelectedIndexChanged1"
UPDATE:
If you want to avoid postback for some events in your code do :
If isPostBack = True
//Don't fill form stuff
Else
//Fill form stuff
End If
First try to check what value is coming in your javascript function.
If its not showing the selceted value use the following code
var index = document.getElementById(selectItem).selectedIndex;
alert("value =" + document.getElementById(selectItem).value);
alert("text =" + document.getElementById(selectItem).options[index].text);
or using jQuery
$("#yourdropdownid option:selected").text();
Ugh, this is driving me mad
Im trying to build up a dynamic menu from a bulletedList, most menu items are plain links however the log out button needs to perform some cleanup code.
I cant for the life of me get the BullettedLists onclick event to fire.
The BulletedList is inside a user control (if that makes a difference)
Any ideas?
Or - any ideas for an alternative, better solution?
Code below
BulletedList
<asp:BulletedList OnClick="menu_Click" runat="server" CssClass="MainMenu" ID="loggedInMenu" DisplayMode="HyperLink" />
Adding an element
loggedInMenu.Items.Add(new ListItem("Logout", ""));
Click handler
protected void menu_Click(object sender, BulletedListEventArgs e)
{
user.logout();
Response.Redirect("Default.aspx");
}
You're using the wrong DisplayMode for your BulletedList control. You should use a DisplayMode of LinkButton. When you use DisplayMode.HyperLink:
Users can click links to move to
another page. You must provide a
target URL as the Value property of
individual items.
This is from the MSDN docs for this control. (It's about 3/4 of the way down the page.)
When you use a BulletedList control in HyperLink mode, the value of your ListItem is the URL that you're navigating to. So your static page HTML controls would use ListItem.Value as the href attribute of the <a> tag.
Here's what the HTML markup looks like when you use a DisplayMode of HyperLink (it's a plain old HTML anchor tag w/ a href):
<li>One</li>
But since you want to postback, you should set the DisplayMode of your BulletedList control to LinkButton. When you do that, you'll enable a postback back to your page and your event handler will trap the event. You can then process the click appropriately then. The event argument that's passed in (of type BulletedListEventArgs) will have an Index property, and that will tell you what item in your list was clicked.
Here's the updated .aspx code that I used:
<asp:BulletedList ID="bullet" runat="server" DisplayMode="LinkButton"
onclick="bullet_Click">
<asp:ListItem Text="One" Value="1">One</asp:ListItem>
</asp:BulletedList>
Everything else is the same except the DisplayMode, which is set to LinkButton. When I use that, then my bullet_Click event handler is fired when I click a list item.
I hope this helps!!