how to pass a value from jsp to controller - spring-mvc

I have some code in JSP as below:
<c:iterate name="list" id="payment" index="idx">
<tr class="gRowEven"
_paid="<c:write name="payment" property="paid"/>">
Now my problem is that I want to call a method in a controller based on the variable _paid. I can do a request.setAttribute("_paid", _paid)
I am assuming it would work. But I am not supposed to do it that way. So I was wondering if there is any other way to do it?

You can pass that value to a hidden input field (on form submit)
<form action='your controller' method='POST'>
...
<input type='hidden' id='newfield' name='newfield' value=''/>
</form>
then you controller can retrieve its value (using request.getParameter('newfield'), or a MVC framework provided method)
Or simply append to the URL if your controller takes GET request
By the way,
request.setAttribute("_paid",_paid);
probably won't work for you. Because this call is only executed when page is loaded, not when you submit the page. Also, when you submit a page, it will have a new fresh request
Edit: (this is what I meant by saying 'pass that value to a hidden input field (on form submit)')
<script type='text/javascript'>
function updateHiddenField() {
var trPaid = document.getElementById('trPaid'); //assume tr field's id is trPaid
//if tr doesn't have an id, you can use other dom selector function to get tr
//element, but adding an id make things easier
var value = trPaid.getAttribute('_paid');
document.getElementById('newfield').value = value;
document.getElementById('form1').submit();
return false;
}
</script>
<form action='your controller' id='form1' method='POST'
onsubmit='javascript:updateHiddenField();'>
...
</form>
Then _paid's value will be passed with request in newfield parameter
And here's how you get the parameter when you are using Spring MVC
#Controller
#RequestMapping("/blah")
public class MyController {
#RequestMapping(value="/morepath" method = RequestMethod.POST)
public ModelAndView test(#RequestParam("newfield") int paid) {
logger.debug("here's the value of paid: " + paid);
}
...

Related

How to POST from one Page Handler to another?

I am working on a ASP.NET Core 2.0 project using Razor Pages (not MVC).
I have the following flow:
User fills out form and POSTs
This page's POST handler validates the info and returns Page() if there are issues. If not, handler saves data to database.
From here, I want the handler to POST to a different page's POST handler with the validated and saved data from Step 2.
How do I POST to another page from within a page handler? Is this the appropriate way to do this kind of thing? The reason I don't want to RedirectToPage() is because I don't want the final page in the sequence to be navigable via GET. The final page should not be accessible via a direct link but should only return on a POST.
I thought about validating/saving the data and setting a boolean "IsValid" and returning the page, checking for that IsValid, and immediately POSTing to the final page via JS. However this feels dirty.
Set the "asp-page" property of the form to your other page. Then set values in the standard way.
<form method="post" asp-page="/pathto/otherpage">
Select Example:<select name="DataForOtherPage">
Then in your controller, bind the value...
[BindProperty]
public string DataForOtherPage { get; set; }
You don't need to cross post!
If possible, you should avoid the cross-post. Do it all under the original action. The action can return a different view by specifying the view name in the View call.
If the target of the cross-post contains complicated logic that you don't want to duplicate, extract it to a common library, and call it from both actions.
For example, instead of
ActionResult Action1()
{
if (canHandleItMyself)
{
return View("View1");
}
else
{
return //Something that posts to action2
}
}
ActionResult Action2()
{
DoSomethingComplicated1();
DoSomethingComplicated2();
DoSomethingComplicated3();
DoSomethingComplicated4();
return View("View2");
}
Do something like this:
class CommonLibrary
{
static public void DoSomethingComplicated()
{
DoSomethingComplicated1();
DoSomethingComplicated2();
DoSomethingComplicated3();
DoSomethingComplicated4();
}
}
ActionResult Action1()
{
if (canHandleItMyself)
{
return View("View1");
}
else
{
CommonLibrary.DoSomethingComplicated();
return View("View2");
}
}
ActionResult Action2()
{
CommonLibrary.DoSomethingComplicated();
return View("View2");
}
If you really want to cross-post
If you insist on using a cross-post, you will have to render a page that does the post, e.g.
<HTML>
<BODY>
<IMG Src="/Images/Spinner.gif"> <!-- so the user doesn't just see a blank page -->
<FORM name="MyForm" Action="Action2" Method="Post">
<INPUT type="hidden" Name="Argument1" Value="Foo">
<INPUT type="hidden" Name="Argument2" Value="Bar">
</FORM>
<SCRIPT type="text/javascript>
document.getElementById("MyForm").submit(); //Automatically submit
</SCRIPT>
</BODY>
</HTML>

Asp.net mvc3 razor with multiple submit buttons

I'm using MVC3 Razor. I have 2 submit buttons setup on my view but the problem I'm having is that both submit buttons cause the validation of the model. I want to hook up individual submit buttons with specific input controls for validation.
I know this is a few months old but the solutions here seemed needlessly complex and there's no accepted answer yet. If you name your inputs the same but give them different values, you can get that value in your controller just by including a string with the name of the input as a variable. This is how I solved this problem:
View:
<input type="submit" id="EnterprisePush" name="btnSubmit" value="Push" />
<input type="submit" id="EnterprisePull" name="btnSubmit" value="Pull" />
Controller:
[HttpPost]
public ActionResult EnterpriseAdmin(int id, string btnSubmit, FormCollection collection)
{
switch (btnSubmit) {
case "Push":
/* Do Something here */
break;
case "Pull":
/* Do Something else here */
break;
}
The browser is always going to submit the entire form regardless of which submit button you press.
The best solution would be to have two submit buttons with the same value for the name attribute and different values for the value attributes.
When you submit the form, the value of the button will be submitted as well. In your action which handles that form submission, you check to see the value of the button and perform the correct validation based on that.
In your form you would have something like this:
<button type="submit" name="Command" value="command1">Do Command #1</button>
<button type="submit" name="Command" value="command2">Do Command #2</button>
Your Form Model would look like this:
public class MyFormModel() {
public string Command {get;set;}
public string SomeOtherVal {get;set;}
}
Your controller\action would look like this:
public ActionResult HandleFormSubmit(MyFormModel model) {
if (model.Command == "command1") {
// do something
} else if (model.Command == "command2") {
// do something else
}
}
Firstly, you can disable client validation on your cancel button simply by adding the CSS class 'cancel' to it. See: Disable client-side validation in MVC 3 "cancel" submit button
Secondly, as well testing the submit element's form name as described above, you can use a custom action selector. Here's mine, which I originally took from the blog post shown in the comment:
/// <summary>
/// Used to vary an action method based on which button in a form was pressed. This
/// is useful but is an anti-pattern because it couples the controller to names
/// used in the form elements.
/// </summary>
/// <remarks>
/// See the example at http://weblogs.asp.net/dfindley/archive/2009/05/31/asp-net-mvc-multiple-buttons-in-the-same-form.aspx
/// </remarks>
public class AcceptButtonAttribute : ActionMethodSelectorAttribute
{
public string ButtonName { get; set; }
public override bool IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo)
{
var req = controllerContext.RequestContext.HttpContext.Request;
return !string.IsNullOrEmpty(req.Form[this.ButtonName]);
}
}
In your controller:
[HttpPost]
[ActionName("Edit")]
[AcceptButton(ButtonName = "Cancel")]
public ActionResult Edit_Cancel(MyModel model)
{
return RedirectToAction("Index");
}
[HttpPost]
[AcceptButton(ButtonName = "Save")]
public ActionResult Edit(MyModel model)
{
// do real work here
}
Note that you need the [ActionName("Edit")] attribute to tell MVC that although using a different method name, it is for the Edit action.
And in your View:
<input type="submit" name="Save" value="Save" />
<input type="submit" name="Cancel" value="Cancel" class="cancel" />
My solution was to do two things. Say we have a Save button and another Add Something button. When user clicks on Save we want client validation and server validation to be performed. For later button we don't want any validation to take place.
Temporarily disable client validation for second button (on click):
<input type="submit" name="submit-button" value="Save" />
<input type="submit" name="submit-button" value="Add Something" onclick="document.forms[0].noValidate = true; document.forms[0].submit();" />
Good thing about it is when JavaScript is disabled the client validation would never have taken place anyway.
Take care of server side
Similar to what Bryan is saying when you click any submit button within a form, the entire form and the clicked submit button value is posted. You can differentiate which button was clicked by the name posted. In example above when user clicks on Save button and we read Request.Form["submit-button"] in controller post action we get "Save". If user clicked on Add Something we would get "Add Something". This is the way HTML is supposed to work.
Now to get around having magic strings all over the place I usually have a public static class within the controller, like so:
public class HomeController
{
public static class Buttons
{
public const string Save = "Save";
public const string AddSomething = "Add something";
}
// Action methods
}
So you can use these for rendering form:
<input type="submit" name="submit-button" value="#HomeController.Buttons.Save" />
And you can easily read the button clicked in controller:
[HttpPost]
public ActionResult Index(Model viewModel)
{
var buttonClicked = Request.Form["submit-button"];
switch (buttonClicked) {
case HomeController.Buttons.Save:
return Save(viewModel);
case HomeController.Buttons.AddSomething:
return AddSOmething(viewModel);
}
return View();
}
In Save method you first ask if ModelState.IsValid and return view model if not but in AddSomething method we will clear any errors:
public ActionResult AddSomething(Model viewModel)
{
ModelState.Clear();
// your code to add something to model
return View(viewModel);
}
This was you keep everything clean, tidy and testable. And you can introduce a constant for submit-button html name attribute. It might be possible to do all the constants with T4MVC too. A similar solution applies to when you need a "auto postback" combo box, except you need a hidden field that is set via onchange event of the select element.
Hope this helps.
Just use this code as a template:
#{
var nextButtonVal = "Next >>";
var backButtonVal = "<< Back";
if (IsPost) {
if(Request["navigate"].Equals(backButtonVal)){Response.Redirect("~/pageFoo");}
if(Request["navigate"].Equals(nextButtonVal)){Response.Redirect("~/pagebar");}
}
}
<input type="submit" value="#backButtonVal" title="Back" name="navigate"/>
<input type="submit" value="#nextButtonVal" title="Next" name="navigate"/>
One final thing I would do is instead of using intelligent strings, use an enum to determine the value for each input tag. Using razor syntax:
#Enum.GetName(typeof(YourEnumType), yourEnum.WhateverValue)
then in your controller:
public ActionResult DoSomethingBasedOnEnumValue(string enumValue)
{
YourEnumType localVar = (YourEnumType)Enum.Parse(typeof(YourEnumType), enumValue);
switch(localVar)
{
case YourEnumType.Action1:
//do something
break;
case YourEnumType.Action2:
//do something else
break;
}
return View();
}
If you want to have separate action for delete, try this.
add a delete action in the controller and mark it as HttpDelete,
[HttpDelete]
public ActionResult Edit(int id, string foo) {
...
}
And in the view,
button name should be X-HTTP-Method-Override and value should be DELETE
<button name="X-HTTP-Method-Override" value="DELETE" formnovalidate="formnovalidate" class="cancel">Delete</button>
note: all most all the browsers don't allow for other HTTP methods, like HEAD, PUT, or DELETE. but by add a header to the HTTP request, X-HTTP-Method-Override, that is supposed to be interpreted by the service and acted upon regardless of the actual HTTP method used. So above code will add a header to the request like X-HTTP-Method-Override: DELETE. and .net framework will do the rest of the things and direct you to delete action.
Submit button name don't come to server side if in all from this situation you are will be use [Remote] attribute for validation model property.

How do I need to get My dropdownlist box value to the controller using asp.net mvc

Hi I have this code in my view..
<%=Html.DropDownList("ProductTemplate",new SelectList(Model.ProductTemplate,"Value","Text"))%>
I know if this dropdownlist box is in between BeginForm submit I can able to access the value in Controller using collection["ProductTemplate"];
if it is not in my beginForm still I can able to access this selected value in controller?
thanks
You could use AJAX to send the value of the currently selected element to a controller action. This is pretty trivial with jQuery:
$.post('/home/foo', { productTemplate: $('#ProductTemplate').val() }, function(data) {
alert(data.success);
});
And to access the selected value in your controller action simply use a parameter:
[HttpPost]
public ActionResult Foo(string productTemplate)
{
// TODO: do something with the selected productTemplate
return Json(new { success = true });
}
If the control in not inside the form tag you will not get its value in controller. The workaround could be.
1) Create a hidden field inside form
2) OnChange event of your dropdown assign the selected value to the hidden field
Edit
<%=Html.DropDownList("ProductTemplate",new SelectList(Model.ProductTemplate,"Value","Text"),new {#onchange="setVal()"})%>
.
.
<form>
.
.
<input type="hidden" id="myval" name="myval"/>
.
.
</form>
<script type="text/javascript">
function setVal()
{
$("#myval").val($("#ProductTemplate").val());
}
</script>
now in your controller you can get the value as collection["myval"]

Validating that a form input is not empty

I have this code for Form Submit..
<input type="submit" runat="server" id="buttonSubmit" value="Add" style="width:100px;" />
My BeginForm is like this..
<% using (Html.BeginForm("Insert", "StudentController", FormMethod.Post, new { #id = "exc-" }))
{%>
I have one textbox in my view I need to check my textbox is empty or not if it is Empty display alert box saying please Enter some value in textbox
other wise go to controler..
Please any body help me out?
thanks
You can do this many ways, but possibly the cleanest is to use Data Annotations on your ViewModel. For example -
public class MyViewModel
{
[Required]
public string MyProperty { get; set; }
}
Now in your View use
<% Html.EnableClientValidation(); %>
just before you start the form. This will cause a JavaScript object to be emitted in the markup sent to the client. The script looks like this example
<script type="text/javascript">
//<![CDATA[
if (!window.mvcClientValidationMetadata) { window.mvcClientValidationMetadata = []; }
window.mvcClientValidationMetadata.push({"Fields":[{"FieldName":"FirstName","ReplaceValidationMessageContents":true,"ValidationMessageId":"FirstName_validationMessage","ValidationRules":[{"ErrorMessage":"The First Name field is required.","ValidationParameters":{},"ValidationType":"required"}]},{"FieldName":"LastName","ReplaceValidationMessageContents":false,"ValidationMessageId":"LastName_validationMessage","ValidationRules":[{"ErrorMessage":"The Last Name field is required.","ValidationParameters":{},"ValidationType":"required"}]},{"FieldName":"EmailAddress","ReplaceValidationMessageContents":false,"ValidationMessageId":"EmailAddress_validationMessage","ValidationRules":[{"ErrorMessage":"The Email Address field is required.","ValidationParameters":{},"ValidationType":"required"}]},{"FieldName":"ZipCode","ReplaceValidationMessageContents":false,"ValidationMessageId":"ZipCode_validationMessage","ValidationRules":[{"ErrorMessage":"Zip Code must be 5 character long.","ValidationParameters":{"minimumLength":0,"maximumLength":5},"ValidationType":"stringLength"},{"ErrorMessage":"Zip Code must be five digits.","ValidationParameters":{"pattern":"\\d{5}"},"ValidationType":"regularExpression"},{"ErrorMessage":"The Zip Code field is required.","ValidationParameters":{},"ValidationType":"required"}]}],"FormId":"form0","ReplaceValidationSummary":false,"ValidationSummaryId":"valSumId"});
//]]>
</script>
This object contains validation metadata that can be used by a client side validation plugin to hook up validation on the client side. The plugin that comes with ASP.NET MVC 2 is the Microsoft AJAX validator and you will need to include these scripts in the page to use the validation (MicrosoftAjax.js, MicrosoftMVCAjax.js and MicrosoftMvcValidation.js in that order).
Alternatively, if you're more comfortable with jQuery, you can get a script in the MvcFutures source that hooks the validation into the jQuery validate plugin (this isn't a fully fledged script and is missing a few pieces, such as getting client side validation summaries). The script is MicrosoftMvcJQueryValidation.js and you can get it here
The advantage of using Data Annotations is that you get the server side validation too and your client and server side validation will validate for the expected values. Also, the Data Annotations allow you to set Error Messages and names for the field labels from the attributes (error messages and display names* can also come from resource files)
*Because MVC2 was compiled against .NET 3.5 version of Data Annotations, display name cannot be set from resource files. There is a workaround to this - DisplayName attribute from Resources?.
NOW THE EASY WAY
Just set up a submit event handler on the form
var form = document.getElementById('exc-');
var oldSubmit = form.onsubmit || function() {};
form.onsubmit = function() {
var input = document.getElementById('myinput');
if (input.value === '') {
alert('please Enter some value in textbox');
return false;
}
oldSubmit();
}
or with jQuery
$('#exc-').submit(function() {
if ($('#myinput').val() === '') {
alert('please Enter some value in textbox');
return false;
}
});

Retrieving data from Html.DropDownList() in controller (ASP MVC) | string returned?

I have the following problem:
I have a form in site/banen (currently local running webserver) which is using a SQL database. The link is made using ADO.net and is instantiated in the controller in the following way:
DBModelEntities _entities;
_entities = new DBModelEntities(); // this part is in the constructor of the controller.
Next, I use this database to fill a Html.DropDownList() in my view. This is done in two steps. At the controller side we have in the constructor:
ViewData["EducationLevels"] = this.GetAllEducationLevels();
and a helper method:
public SelectList GetAllEducationLevels()
{
List<EducationLevels> lstEducationLevels = _entities.EducationLevels.ToList();
SelectList slist = new SelectList(lstEducationLevels, "ID", "Name");
return slist;
}
In the view I have the following:
<% using (Html.BeginForm()) {%>
<fieldset>
<legend>Fields</legend>
<!-- various textfields here -->
<p>
<label for="EducationLevels">EducationLevels:</label>
<!-- <%= Html.DropDownList("EducationLevels", ViewData["EducationLevels"] as SelectList)%> -->
<%= Html.DropDownList("EducationLevels", "..select option..")%>
</p>
<p>
<input type="submit" value="Create" />
</p>
</fieldset>
<% } %>
Now, the form is rendered correctly when I browse to the create page. I can select etc. But when selected I have to use that value to save in my new model to upload to the database. This is where it goes wrong. I have the following code to do this in my controller:
//
// POST: /Banen/Create
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create(FormCollection form)
{
// set rest of information which has to be set automatically
var vacatureToAdd = new Vacatures();
//vacatureToAdd.EducationLevels = form["EducationLevels"];
// Deserialize (Include white list!)
TryUpdateModel(vacatureToAdd);
// Validate
if (String.IsNullOrEmpty(vacatureToAdd.Title))
ModelState.AddModelError("Title", "Title is required!");
if (String.IsNullOrEmpty(vacatureToAdd.Content))
ModelState.AddModelError("Content", "Content is required!");
// Update the variables not set in the form
vacatureToAdd.CreatedAt = DateTime.Now; // Just created.
vacatureToAdd.UpdatedAt = DateTime.Now; // Just created, so also modified now.
vacatureToAdd.ViewCount = 0; // We have just created it, so no views
vacatureToAdd.ID = GetGuid(); // Generate uniqueidentifier
try
{
// TODO: Add insert logic here
_entities.AddToVacatures(vacatureToAdd);
_entities.SaveChanges();
// Return to listing page if succesful
return RedirectToAction("Index");
}
catch (Exception e)
{
return View();
}
}
#endregion
It gives the error:
alt text http://www.bastijn.nl/zooi/error_dropdown.png
I have found various topics on this but all say you can retrieve by just using:
vacatureToAdd.EducationLevels = form["EducationLevels"];
Though this returns a string for me. Since I'm new to ASP.net I think I am forgetting to tell to select the object to return and not a string. Maybe this is the selectedValue in the part where I make my SelectList but I can't figure out how to set this correctly. Of course I can also be complete on a sidetrack.
Sidenote: currently I'm thinking about having a seperate model like here.
Any help is appreciated.
You can't return an object from usual <SELECT> tag wich is rendered by Html.DropDownList() method, but only string variable could be returned. In your case ID of EducationLevels object will be send to the server. You should define and use one more custom helper method to reconstruct this object by ID.

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