Swagger show decimal as 0.00 instead of 0

Question

I have this class:

public class CostDto
{
    public int Id{ get; set; }
    public decimal? Price { get; set; }
}

In the swagger it shows this:

{
    "Id": 0,
    "Price": 0
}

And I would prefer this:

{
    "Id": 0,
    "Price": 0.00
}

This would more clearly indicate to the user that the returned value of Price is of type decimal, not integer. It this possible at all in swagger? I found some posts referring to something like this, but it doesn't seem to work:

services.AddSwaggerGen(options =>
{
    options.MapType<decimal>(() => new OpenApiSchema { Type = "number", Format = "decimal" });
    options.MapType<decimal?>(() => new OpenApiSchema { Type = "number", Format = "decimal", Nullable = true });
});

Answer 1

You could try this:

public class DecimalSchemaFilter : ISchemaFilter
{
    public void Apply(OpenApiSchema schema, SchemaFilterContext context)
    {
        if (schema.Type == "number" && schema.Format == "decimal")
        {
            schema.Example = OpenApiAnyFactory.CreateFromJson("0.01");
        }
    }
}

services.AddSwaggerGen(options =>
{
    options.SchemaFilter<DecimalSchemaFilter>();

    options.MapType<decimal>(() => new OpenApiSchema { Type = "number", Format = "decimal" });
    options.MapType<decimal?>(() => new OpenApiSchema { Type = "number", Format = "decimal", Nullable = true });
});