Question

I have a ProductService class that defines the following methods. It doesn’t work, as I will explain further below, but it gives the compile error CS1061: ‘ProductService’ does not contain a definition for ‘GetByid’. Unless I’ve dropped the ball on method overloading, why is the public overload of GetById not seen by other code?

public IEnumerable<Product> ListActiveByCatId(Guid catId) {
    return _entityContext.Products
        .Include("Category")
        .Where(p => p.Category.id == catId);
}

public Product GetById(string productId) {        
    return new Product();
}

private Product GetByid(Guid productId) {
    return _entityContext.Products.First(p => p.id == productId);
}

I have the following code using a ProductService, and the two compile errors are both on this call:

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack) {
        var productId = Request["productId"];
        if (productId == null) {
            // TODO How to get the actual parameter, not default parameter.
            productDetailDataSource.SelectParameters["productId"].DefaultValue = DefaultProductId;
        }
        *itemTitleLabel.Text = _productService.GetByid(productId).Name;*
    }
}

The exact compiler error is:

C:\SCS\Products\Details.aspx.cs(21,51):
error CS1061: ‘ProductService’ does
not contain a definition for ‘GetByid’
and no extension method ‘GetByid’
accepting a first argument of type
‘ProductService’ could be found (are
you missing a using directive or an
assembly reference?)

Line 21 is the one I attempted to emphasise, i.e. the one with asterisks around it in the above calling code.

Answer 1

GetByid != GetById

You’ve got a casing issue.