We Keep Coding

How to change button css on pageload

Hi and thanks in advance...
I have a button that I want change the css on pageload in c# and asp.net. Right now, on pageload, I am only able to change the text. When the text contains "ADD" I need it to be green, else blue.
Inside of a gridview I have this:
ASP.NET
<asp:TemplateField HeaderText="Tower">
<ItemTemplate>
<asp:Button ID="Button_Detail" CssClass="page-btn blue" CausesValidation="false"
CommandArgument='<%#Eval("idRangeList") %> ' CommandName="Detail" runat="server"
Text='<%# getButtonText(Eval("idRangeList")) %>' OnClick="btnDetails_Click">
</asp:Button>
</ItemTemplate>
</asp:TemplateField>
c#
protected string getButtonText(object o)
{
String btnText;
int rID = Convert.ToInt32(o);
WISSModel.WISSEntities context = new WISSModel.WISSEntities();
var text = (from t in context.Towers
where t.isDeleted == false && t.fkRangeList == rID
select t);
if (text.Count() == 0)
{
btnText = "3. ADD";
}
else
btnText = "Details";
return btnText;
}
I am up for either a jquery or c# solution.
I have tried both and I am stuck. On the C# side, I am not able to access the ButtonID.
For JS I tried this, but its not doing anything:
function textCheck() {
//var buttonDetails = $("Button_Detail");
if($("Button_Detail:contains('ADD')")){
$("Button_Detail").css("green v2");
}
}

you need to try:
if($(".page-btn").val()=='ADD'){
$(this).removeClass().addClass('.page-btn green');
}

This line will not work:
$("Button_Detail").css("green v2");
It needs to be:
$("Button_Detail").addClass("green v2");
However this will still not work as your selector isn't correct. It either needs to have a # for IDs or a . for classes. Given that .NET's IDs are changable it's far easier to give your control a unique class and use that.
In your case:
$(".page-btn").addClass("green v2");
The jQuery css function is for adding specific CSS properties to an element.
http://api.jquery.com/css/
If you want to manipulate which classes an element has you should look at the class attribute documentation:
http://api.jquery.com/category/manipulation/class-attribute/

How to make textbox visible when previous textbox contains text

I have a WebForm in which i need to place around 30 textboxes mainly to enter barcode scanned data. I am making only the first textbox visible and i want the next textbox to be visible only when the previous textbox is filled with some text. I tried using 'If' condition as well in the textbox on selected change but it doesn't work. Any solutions?

You should use java-script for this because if you will use server side function for this then It will go to server so many times by this your application performance also will decrease.
So create a java-script function that will accept one argument. This argument will take next text box id (text box u want to display).
call this javascript function like this:- onkeyup="calgrid(this,"TextBox2");"
pass nexttextbox id in place of TextBox2...
<script type="text/javascript" language="javascript">
function calgrid(firsttextbox,nexttextbox)
{
var id=firsttextbox.id;
var lastindex= id.lastIndexOf("_");
var strclnt=id.slice(0,lastindex+1);
var txtboxvalue=document.getElementById(firsttextbox).value;
if(txtboxvalue!="")
{
document.getElementById(strclnt+nexttextbox).style.visibility='visible';
}
else
{
document.getElementById(strclnt+nexttextbox).style.display = "none";
}
}
</script>
note:- If you will do visible=false from textbox property then we cannt do visible=true from javascript. So Set style for all textbox style="display:none"

You can resolve your problem by Jquery.
I have make a sample code where i have take four Textbox. Initially only first text box is visible in Web form, when user enter some values in first TextBox next Textbox is automatically display if Previous textbox have a value if not next textbox is not visible.
Sample code is given below :
<input type="text" />
<input type="text" />
<input type="text" />
<input type="text" />
$('input:text:not(:eq(0))').hide()
$('input').on("change paste keyup", function () {
if ($(this).val().length > 0) {
$(this).next().show();
}
else
{
$(this).next().hide();
}
});
I have made sample application for same ,please click on given link for Demo
See Demo application
It's at Client side code so its performance is so fast rather than Server Side.
Please vote me if you feel your problem is resolved by my idea.

I'd name these text boxes similarly like "textbox1", "textbox2", "textbox3" so you can easily find the index of current text box. Then you can use KeyDown event to control what will be shown and what not. This is not a working example but it should give you a good direction.
int currentIndex = 1;
private void TextBox1_KeyDown(object sender, KeyEventArgs e)
{
TextBox t = Controls["TextBox" + (currentIndex + 1).ToString()] as TextBox;
t.Visible = true;
currentIndex +=1;
}

Use can use Keydown event in your first textbox

try this code
initially set flag=1 as first textbox is going to be by default visible
private void visibleTextBox(Control c)
{
int flag = 1;
foreach (Control c1 in c.Controls)
{
if (c1.GetType() == typeof(TextBox))
{
if (flag == 1)
{
((TextBox)c1).Visible = true;
}
else
{
((TextBox)c1).Visible = false;
}
if (((TextBox)c1).Text != "")
{
flag = 1;
}
else
{
flag = 0;
}
}
}
}

Comparatively simple solution in JavaScript. The code should be somehow like this.
Define onchange event on text boxes like this:
<asp:TextBox ID="txt1" runat="server" onchange="show('txt1', 'txt2');"></asp:TextBox>
<asp:TextBox ID="txt2" runat="server" onchange="show('txt2', 'txt3');" Style="visibility: hidden;"></asp:TextBox>
Then use this JavaScript code to show the next TextBox conditionally. Put this code in the head tag of the page:
<script type="text/javascript">
function show(txtCurrent, txtNext) {
var valueCurrent = document.getElementById(txtCurrent).value;
//alert(valueCurrent);
if (valueCurrent.length > 0) {
document.getElementById(txtNext).style.visibility = 'visible';
}
else {
document.getElementById(txtNext).style.visibility = 'hidden';
}
}
</script>

How to pass Event Validation when editing a select list from JavaScript

I have two select lists in my ASP.NET site that are filled by the server with some elements.
// .aspx
<asp:dropdownlist id="abc" runat="server"></asp:dropdownlist>
<asp:dropdownlist id="def" runat="server"></asp:dropdownlist>
// .aspx.cs
abc.Items.Add(new ListItem("element1", "value1"));
def.Items.Add(new ListItem("element1", "value1"));
Due to too complicated reasons to explain right now, I also need to modify the options of the select lists with JavaScript, adding some values.
// In the <head> of the .aspx page
var abcList = document.getElementById("abc");
var defList = document.getElementById("def");
var newAbcElement = new Option("element2", "value2", false, false);
var newDefElement = new Option("element2", "value2", false, false);
abcList.options[abcList.length] = newAbcElement;
defList.options[defList.length] = newDefElement;
Of course, this will mess up Even Validation as soon as I send the form back to the server (be it by submitting or as a PostBack from some other form elements with AutoPostBack="true").
Invalid postback or callback argument. Event validation is enabled using in configuration or <%# Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.
Now, I don't have the resources and budget to completely overhaul the whole page design, so: What is the fastest and easiest way to change the dropdownlist that does not mean I have to rewrite the whole thing?
So that the values added via JavaScript are recognized by my CodeBehind file when submitting the form?

Ok, here is one more option for you. You can add those items to your lists using AsyncPostBackTrigger.
Some hidden fields:
<asp:TextBox ID="newItemsForAbc" runat="server" style="display:none;"></asp:TextBox>
<asp:TextBox ID="newItemsForDef" runat="server" style="display:none;"></asp:TextBox>
<asp:Button ID="addNewItems" runat="server" OnClick="addNewItems_Click"
style="display:none;" />
The Update Panel:
<asp:UpdatePanel runat="server" ID="UpdatePanel" UpdateMode="Conditional">
<ContentTemplate>
<asp:dropdownlist id="abc" runat="server"></asp:dropdownlist>
<asp:dropdownlist id="def" runat="server"></asp:dropdownlist>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="addNewItems" EventName="Click" />
</Triggers>
</asp:UpdatePanel>
JS Function for doing an async post back:
<script type="text/javascript"> function UpdateStuff(value1, value2)
{
var abcItems = document.getElementById("<%= newItemsForAbc.ClientID %>");
var defItems = document.getElementById("<%= newItemsForDef.ClientID %>");
abcItems.value=value1;
defItems.value=value2;
__doPostBack("<%= addNewItems.ClientID %>","");
}
</script>
Server-side function that handles button click:
protected void addNewItems_Click(object sender, EventArgs e)
{
string[] n1 = newItemsForAbc.Text.Split(';');
string[] n2 = newItemsForDef.Text.Split(';');
foreach(string i in n1)
{
abc.Items.Add(new ListItem(i, i));
}
foreach(string i in n2)
{
def.Items.Add(new ListItem(i,i));
}
}
To Update Your Lists:
var newAbcElements = "Element1;Element2;Element3";
var newDefElements = "Element4;Element5";
UpdateStuff(newAbcElements, newDefElements);
Final note:
This piece of code probably will not do the job for you as it is. You may need to change the way you store new items in a string, thus splitting/parsing would change too. You may even need different strings for displaying a list item and its actual value. But I believe you get the basic idea.

You can disable the ViewState entirely for the DropDownList.
<asp:dropdownlist id="abc" runat="server" EnableViewState="false"></asp:dropdownlist>
To your question update:
This changes the question quite a lot. The new question is answered here: Invalid postback or callback argument. Event validation is enabled using '<pages enableEventValidation="true"/>'

You have a few options.
First, you might rewrite your code so that the server side generates all possible items for the DropDownList and then in your JavaScript remove the unneeded items instead of adding new ones.
Second option is to create a custom class derived from System.Web.UI.WebControls.DropDownList. The class should contain the one method shown below. The important piece is that your custom class will not have the System.Web.UI.SupportsEventValidationAttribute added to it - so DropDownList base methods will skip the event validation automatically. Now replace the usage from <asp:dropdownlist> to your method.
In case you can't modify the .aspx code (or you have a ton of dropdownlists to replace) you might use tag mapping in your configuration.
namespace Project.MyWebControls
{
public class MyDropDownList : System.Web.UI.WebControls.DropDownList
{
protected override bool LoadPostData(string postDataKey, NameValueCollection postCollection)
{
if (base.LoadPostData(postDataKey, postCollection))
return true;
// this means that the value selected was not present in the .Items collection
string[] values = postCollection.GetValues(postDataKey);
if (values == null || values.Length == 0)
return false;
// add the value to the Items collection so that it can be processed later on.
this.Items.Add(new ListItem("Custom value created by JavaScript", values[0]));
this.SetPostDataSelection(this.Items.Count - 1);
}
}
}
Note that depending on your code you might want to remove these custom values from the Items collection before rendering.
Sample for the .aspx file:
<%# Register TagPrefix="my" Namespace="Project.MyWebControls" Assembly="Project" %>
<my:MyDropDownList runat="server" ...></my:MyDropDownList>

How to Check if ListBox is Empty on Client-Side

I created a javascript confirm as below.
<script Type="Text/Javascript">
function CheckListBox(lvi)
{
if(lvi == "")
{
if(confirm("Are you sure?"))
{
return true;
}
else
{
return false;
}
}
}
</script>
I need to test if the ListBox.Items control is empty... I already made reference on my aspx page
<script language="javascript" type="text/javascript" src="/JS/confirm.js"></script>
I want to know how to call it on my aspx.cs page . . . So I can pass the parameter:
string oi = Listbox_Clubes.Items.Count.ToString();//Its the parameter I want to pass

See this link for how to execute javascript from code behind
protected void Page_Load(object sender, EventArgs e)
{
ScriptManager.RegisterStartupScript(this, this.GetType(), Guid.NewGuid().ToString(), "CheckListBox(" + Listbox_Clubes.Items.Count.ToString() + ");", false);
}
Note: you must add a ScriptManager control in aspx page.

For your javascript, you can get the value without the code-behind (this assumes the script code is in the same page, in order to get the client ID):
<script>
function ClickListBox() {
if ($("#<%= Listbox_Clubes.ClientID %>").val() === null) {
if (confirm("Are you sure?")) {
return true;
}
else {
return false;
}
}
}
</script>
Similarly, you don't use javascript to validate on the server side. The code you posted will return all items in the ListBox. Here is one way to get the count of the number of selected items (I'm using .ToString() based on the OP code example):
string oi = Listbox_Clubes.Items.Cast<ListItem>().Where(i => i.Selected).Count().ToString();
However, there is no reason why you would get this value and pass it back to the client-side to do validation (what it sounds like you want to do in your post). Mainly because this involves a post-back, and client-side validation, by its nature, should occur before post-back. Also, you will still need to do server-side validation, even when you have client-side validation.
Related: in the code-behind, you can test to see if anything is selected by:
bool hasValue = Listbox_Clubes.SelectedItem != null;
The .SelectedItem returns the selected item with the lowest index in the list control. When nothing is selected, this value is null... so you know if the value isn't null, then at least one item was selected.
If you want to require that they choose at least one item, you can use a RequireFieldValidator and let that handle both validations. If you haven't done much with ASP.NET validators, that would be one good thing to read up on.
It sounds like you probably should read more about client-side validation and server-side validation and how to use them... because it seems like you are mixing them up.
The count code is a modified version of code in ASP:ListBox Get Selected Items - One Liner?

Fetch JS return value in server side page_load event in asp.net

I have an aspx master/content page scenario. The parent page has an IFrame which points to a child.aspx. The child.aspx has a checkbox, On page_load of child.aspx, I want to show/hide the checkbox depending on the following logic:
- if the child.aspx is opened directly, then I have to show the checkbox.
- if the child.aspx is opened in the IFrame, then I have to hide the checkbox.
Basically, I want to check in child.aspx, if it contains a parent window then hide the checkbox control otherwise show it.
I will prefer the show/hide code in codebehind in Page_load event as I have to execute some more logic depending on whether the it is opened from parent window or not.
Till now I did the following:
In child.aspx
<asp:Content ID="Content1" ContentPlaceHolderID="Main" Runat="Server">
<script language="javascript" type="text/javascript">
function DoesParentExists()
{
var bool = (parent.location == window.location)? false : true;
var HClientID ='<%=hfDoesParentExist.ClientID%>';
document.getElementById(HClientID).Value = bool;
}
</script>
<div>
<h2>Content - In IFrame</h2>
<asp:HiddenField runat="server" id="hfDoesParentExist" />
<asp:CheckBox ID="chkValid" runat="server" />
<asp:ImageButton ID="ImageButton_FillW8Online" ImageUrl="~/images/expand.gif"
OnClick="btnVerify_Click" runat="server" style="height: 11px" />
</div>
</asp:Content>
in client.aspx.cs
protected void Page_Load(object sender, EventArgs e)
{
Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "DoesParentExists", "DoesParentExists()", true);
if (hfDoesParentExist.Value == "true")
{
chkValid.Visible = false;
}
}
Using RegisterClientScriptBlock, I get error in JS. That the object hfDoesParentExist doesn't exist 'coz the control is not yet created. Right? I tried using RegisterStartupScript but in codebehind I always get null in hidden variable. I don't want to use the on button click or something like it. I need it on page_load event only. How to resolve the issue?

This line:
document.getElementById(HClientID).Value = bool;
Should be: (lower case value)
document.getElementById(HClientID).value = bool;
Also you cannot check the value of a hidden field set by javascript register callback, in the current executing context on the server side.
I would move the logic to the client side to hide or show the checkbox. If the field must indeed be removed from the page you can do that as well with javascript.
function DoesParentExists()
{
var bool = (parent.location == window.location)? false : true;
var cehckboxId ='<%=chkValid.ClientID%>';
if(bool){
document.getElementById(cehckboxId).style.display = 'none';
}
else {
document.getElementById(cehckboxId).style.display = 'block';
}
}
You may want to wrap the checkbox with a div and hide the container also to include the label.

To do it server-side, I would rely on a querystring parameter. Have the parent page load the child page by appending ?inframe=1. Then check for that value in your Page_Load.