.netcore asp-for decimal loses decimal places

Question

I am running into an issue where I am losing decimal places when using the asp-for tag helper in my view. It seems to always round up to 2 decimals, while I want to have it round up to 3 decimals (in this case).

I can see in my debugger that the value in the Model has 3 decimal places as e

But then in my view, it's being displayed as 1.28 instead of 1.275:

This is my form's view, as you can see there's nothing special really going on (the asp-has-error tag helper is a custom tag helper for this project):

<div class="form-group row">
        <label asp-for="RatePercentage" class="col-lg-4 col-form-label"></label>
        <div class="col-lg-8">
                <input asp-for="RatePercentage" asp-has-error="@Html.HasErrorFor(m => m.RatePercentage)" class="form-control"/>
        </div>
</div>

Any ideas how I can get 3 decimal places to show here?

Answer 1

That's just the default. You can use the DisplayFormat attribute to make it whatever you like:

[DisplayFormat(DataFormatString = "{0:[format]}", ApplyFormatInEditMode = true)]
public decimal RatePercentage { get; set; }

Where [format] is the format string you want. See Standard Numeric Format Strings and Custom Numeric Format Strings.

Answer 2

Another way to stop the tag-helper from applying this default formatting is to explicitly specify the input element's type attribute and assign it as text like so:

<input type="text" asp-for="RatePercentage" …/>

Then you get the 'raw' decimal value in the input control and you can use an edit-mask or format it yourself some other way and not automatically lose the precision of the value that happens otherwise.