Optional Column Header Template

[Marc Simkin]

Is there a way to have the column header template be optional?  Depending upon some values in my data, I might need to use a header template for a specific column, otherwise, I would like the have the default behavior.

I tried placing an if statement inside the <GridColumn/> element like this:

<GridColumn Field= "" FieldType="" >
     @if (_useHeaderTemplate)
     {
         <HeaderTemplate></HeaderTemplate>
     }
</GridColumn>

This results in a compile error of "Unrecognized child content inside component ...."

I then tried

<GridColumn Field= "" FieldType="" >
     <HeaderTemplate>
          @if (_useHeaderTemplate)
          {
            <div>Custom Header</div>
          }
     </HeaderTemplate>
</GridColumn>

This results in no text being rendered for the column header.

I'm trying to avoid (a) duplicating the <GridColumn/> configuration for both the  true and false evaluations of the if statement; (b) I don't want to take over the complete rendering and management of the grid column header.  I still want the framework to handle that.

Thanks

-marc

 

 

[Dimo]

Hello Marc,

The GridColumn component does not have a ChildContent property of type RenderFragment. That's why you can't place arbitrary content inside it (such as conditional statements or anything other than predefined <...Template> tags).

On the other hand, you are not taking over the whole rendering if you have the conditional statement inside the <HeaderTemplate>. The following two columns will render identical header cell content:

<TelerikGrid Data="@GridData"
             TItem="@Product"
             Pageable="true"
             Sortable="true"
             FilterMode="GridFilterMode.FilterMenu">
    <GridColumns>
        <GridColumn Field="@nameof(Product.Name)" Title="Product Name" />
        <GridColumn Field="@nameof(Product.Name)">
            <HeaderTemplate>
                Product Name
            </HeaderTemplate>
        </GridColumn>
    </GridColumns>
</TelerikGrid>

@code {
    List<Product> GridData { get; set; }

    protected override void OnInitialized()
    {
        GridData = new List<Product>();
        var rnd = new Random();

        for (int i = 1; i <= 7; i++)
        {
            GridData.Add(new Product()
            {
                Id = i,
                Name = "Product " + i,
                Price = (decimal)rnd.Next(1, 100),
                ReleaseDate = DateTime.Now.AddDays(-rnd.Next(60, 1000)),
                Active = i % 3 == 0
            });
        }
    }

    public class Product
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public decimal Price { get; set; }
        public DateTime ReleaseDate { get; set; }
        public bool Active { get; set; }
    }
}

Regards,
Dimo
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