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c#expressiveannotations

In Expressive Annotations using the AssertThat attribute - how to modify the error message at runtime or pass in string values

In Expressive Annotations, using the "AssertThat" attribute is it possible to modify the error message at runtime? I am working in ASP.NET MVC Classic environment and needed to add to my existing validations. The new validation would check that the date entered was within a specific date range and I wanted to incorporate the boundary date in the error message but the date is not a constant and can change (every 3-4 months). The issue is that the "AssertThat" ErrorMessage attribute only seems to allow constant strings.

The code looks something like this

[AssertThat ("!IsDateBeforeDataRange(BeginDate.Value)"
, ErrorMessage ="Requested Date is prior to data ingest range ")]
public DateMvcModel BeginDate { get; set; }

This works, but I wanted to incorporate the actual date boundary in the error message like this:

[AssertThat ("!IsDateBeforeDataRange(BeginDate.Value)"
, ErrorMessage ="Requested Date is prior to data ingest range{IngestDataDtBegnin} ")]

But this is not allowed. In the examples for "AssertThat" the default error message does incorporate string interpolation, but I can't figure how to pass my own values in.

Solution

  • A bit late for the OP, but yes this can be done, using the curly bracket syntax in your second snippet.

    The trick is the date has to be stored in a property, and posted into the action.

    If the date property is alresdy used in your view, it should just work, but if it is a value that is not currently displayed in your view, you'll need to store it in a hidden field so that the value will be available for both client side and server side.