ASP.NET MVC Double with Dot Decimal separator get comma separator once supplied in html form

Question

i'm stuck and cannot find easy way to solve this issue, let's suppose i have below model:

public class FooModel
{
  string name{get;set;}
  double doubleFoo{get;set}
}

i built a class, usable from a HTMLform, where user can upload an excel file, and this class will read values to create a new fooObject, with properties like FooModel.

FooModel FooObjectFromExcelValues = new FooModel()
{
 name = nameFromExcel,
 doubleFoo = doubleFooFromExcel, /* <= this variable contains dot decimal separation, and look like "0.061065380952380954" */
}

I have checked, FooObjectFromExcelValues.doubleFooFromExcel is dot separated value.

Now, my controller return a view, where a form is populated with values sent from FooObjectFromExcelValues.

<form asp-action="FooAdd">

<div>
<label asp-for="name" class="control-label"></label>
<input asp-for="name" class="form-control"/>
<span asp-validation-for="name" class="text-danger"></span>
</div>

<div>
<label asp-for="doubleFoo " class="control-label"></label>
<input asp-for="doubleFoo " class="form-control"/>
<span asp-validation-for="doubleFoo " class="text-danger"></span>
</div>

</form>

form once populated with object sent from excel

here come the trouble, doubleFoo is now showed on my form with comma separation like "0,061065380952380954", and i can't send the form to add object to database.

Why ? How can i easily solve this ?

tried several from stackoverflow without success

Answer 1

doubleFoo is now showed on my form with comma separation like "0,061065380952380954", and i can't send the form to add object to database.

Why ? How can i easily solve this ?

Well, in some locales, commas are used as decimal separators instead of dots. This discrepancy causes issues when the form data is sent back to the server, as the server expects a dot-separated decimal value.

I order to fix the issue, in the controller, convert the double value to a string with a dot as the decimal separator before passing it to the view. This ensures that the correct format is displayed in the form.

You could do as following:

var fooObjectFromExcelValues = new FooModel
{
    name = "Sample Name",
    doubleFoo = 0.061065380952380954
};


ViewBag.DoubleFooString = fooObjectFromExcelValues.doubleFoo.ToString(CultureInfo.InvariantCulture);

View:

@model FooModel

<form asp-action="FooAdd" method="post">
    <div>
        <label asp-for="name" class="control-label"></label>
        <input asp-for="name" class="form-control" />
        <span asp-validation-for="name" class="text-danger"></span>
    </div>

    <div>
        <label asp-for="doubleFoo" class="control-label"></label>
        <input asp-for="doubleFoo" class="form-control" value="@ViewBag.DoubleFooString" />
        <span asp-validation-for="doubleFoo" class="text-danger"></span>
    </div>

    <button type="submit">Submit</button>
</form>

When you would submit the from value, you could cross check the correct value once again:

if (double.TryParse(model.doubleFoo.ToString(CultureInfo.InvariantCulture), NumberStyles.Float, CultureInfo.InvariantCulture, out double parsedDouble))
{
    model.doubleFoo = parsedDouble;

    // Simulate adding the object to the database
    // db.FooModels.Add(model);
    // db.SaveChanges();

    return RedirectToAction("Index"); 
}

Output:

Note: Please refer to this official document for additional information.