ASP.NET MVC OnChange Razor - c#

I have searched if there is any way that ASP.NET MVC can handle OnChange event without using neither Javascript but all the results return the OnChange of DropdownList...
Is there any way to achieve this? I want to OnChange an file input to post file data.

<select id="myElement">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
</select>
you can use javascript code
document.getElementById("myElement").addEventListener("change",function(e){
e.currentTarget.value
});

Without JavaScript, no, if you want to do anything dynamically, you need JavaScript.
As HTML is just for markup, and nothing else, you'll have to have the page refresh, or use JavaScript.

Related

Using session variables in ASP Core 1.1

I want to fill a combo box located in the top menu; the menu is in the file _layout.cshtml and I don't want to fill from every action I call in my application.
There is a way to fill the combo using a session variable from the razor view?
Thanks
Your question is very broad and assumes a lot, Do you need to even store the values, can you just add a select list?
<select>
<option value="1">option 1</option>
<option value="2">option 2</option>
<option value="3">option 3</option>
</select>

ASP MVC3 - Marking Option as Selected

I have a form that has 2 select boxes (Country and State) that have their available options contained in partial HTML files, due to their size.
In the event of a validation error, I want to mark the option the user originally selected as "selected".
Since the options are contained in a partial HTML file, I am not sure that this is even possible:
Any suggestions would be great. Thanks
// Inside the View
<select name="State" id="State">
#Html.Partial("States", Model);
</select>
#Html.ValidationMessageFor(model => model.State)
The partial simply contains the HTML:
<option value="AL">Alabama</option>
<option value="AK">Alaska</option>
<option value="AZ">Arizona</option>
<option value="AR">Arkansas</option>
<option value="AA">Armed Forces Americas</option>
<option value="AE">Armed Forces Europe, Middle East</option>
[...]
Instead of using strange Partial, why you just do not use helper DropDownList. You can find many examples, like this one http://peternewhook.com/2013/02/asp-net-mvc-selectlist-selectedvalue-dropdownlistfor/

Dropdown list options

I am using this code on my Master page and wants to display option name on the reffered page
<select name=menu onchange="location.href=(menu.options[menu.selectedIndex].value)">
<option value="http:google.com">Google</option>
<option value="http:myurl.com">URL</option>
</select>
You need to use this to refer to event source object instead of menu the name of html element. You also have wrong url form and need to change it from http:google.com to http://google.com
Live Demo
<select name=menu onchange="window.location.href=(this.options[this.selectedIndex].value)">
<option value="http://www.google.com">Google</option>
<option value="http://www.stackoverflow.com">stackoverflow</option>
</select>​

Using databinding to populate a HtmlSelect with optgroup elements in asp.net

I am using asp.net and have a HtmlSelect element on my page (with runat="server"). Normally I will just set the DataSource to some loaded data and DataBind. However in this case the data has one level of hierarchy and I want to represent this in the HTML with an optgroup. Google hasn't come up with any joy - is this even possible?
I've had a similar problem to solve and this is how I did it. Before I continue I did find all sorts of re-fracturing methods for lists, which probably do work. However, I did not think this the best route to go for my solution. Here's what I did:
I also needed to know which option a user selected in the drop down list but found that you can't build drop down list with option groups in ASP.net. So to do this I just built a simple <select> with <optgroup>'s and <option>'s in each group. Then I placed a <div> with a hidden textbox, which had the runat="server" set. I set the "onchange" event, on the select, to change the text value of the hidden textbox to whatever the value the option was, which was selected by the user, using javascript. Then, when the post back occurs, the code behind had access to the value the user selected, via the hidden textbox's runat="server". Problem solved! The code looks something like this:
Code in the HTML (aspx):
<div id="selectDiv">
<select id="selectItems" onchange="document.getElementById('hiddenselectDiv').getElementsByTagName('input')[0].value = this.options[this.selectedIndex].value;">
<optgroup label="Johannesburg">
<option value="Wilropark">Wilropark</option>
<option value="Bryanpark">Bryanpark</option>
<option value="Hurlingham">Hurlingham</option>
<option value="Midrand ">Midrand </option>
<option value="Glenvista">Glenvista</option>
<option value="Sunninghill">Sunninghill</option>
<option value="Edenvale ">Edenvale </option>
<option value="Parkhurst">Parkhurst</option>
</optgroup>
<optgroup label="Cape Town">
<option value="Tokai">Tokai</option>
<option value="Durbanville">Durbanville</option>
</optgroup>
<optgroup label="Durban">
<option value="Musgrave">Musgrave</option>
</optgroup>
<optgroup label="Pretoria">
<option value="Hatfield">Hatfield</option>
</optgroup>
</select>
</div>
<div id="hiddenSelectDiv">
<!--
Note: You probably want to set the hidden value to the first item you have seleced when you build the <select> object.
-->
<input type="hidden" id="selectedItem" value="Wilropark">
</div>
In the Code behind (C#):
if (!string.IsNullOrEmpty(selectedItem.Value))
{
//validation or whatever you want....
}
I've been looking around for the same thing, and it doesn't look like ASP supports this natively. One Google search found someone recommending a library at http://www.codeplex.com/SharpPieces, but I've never used it and I don't know how good it is. Other people talk about writing your own renderer for optgroup support.

Call JQuery from C# PageLoad

Is there any way how to call JQuery function from PageLoad C# file?
Basically I have some selects, some inputs which are not generated by C# code but are defined in .aspx file manually. When I send form get query to another page I would like to set same variables that are defined in querystring. I know how to do that when I use runat="Server" but I want pure JQuery solutions without having runat="server" objects.
Example:
Select input:
<form method="get" action="/list/search">
<select id="txtSearchFullTyp" name="typ">
<option value="all">Sell, Rent</option>
<option value="1">Sell</option>
<option value="2">Rent</option>
<select>
</form>
Now after sending querystring to another page I am analyzing querystring and running function with defined parameter.
I want to be able to set form to querystring defined as "typ". I dont know how to do it from C# when I dont have runat="Server" option.
Is there a way to do this?
Thanks.
Here's a code for it. It's quite hacky but nevertheless it answers your question:
<form method="get" action="/list/search">
<select id="txtSearchFullTyp" name="typ">
<option value="all">Sell, Rent</option>
<option value="1">Sell</option>
<option value="2">Rent</option>
<select>
</form>
<asp:Literal runat="server" ID="litJqueryCode"/>
and from the code behind you can do the following
litJqueryCode.Text = "<script type='text/javascript'>$(function(){ $('#txtSearchFullTyp').val('"+ Request.QueryString["dropdownValue"] +"') })</script>";

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