Replace the Placeholders in a Text With the Values of the Object

Platforms: .NET

When working on multi-language websites or apps, or we have to send personalized confirmation emails, we often store the text as a resource in resource files or a database.

This way of working is great to let translators translate the text and the developer build the website/app.

The text can hold different placeholders and the following Nuget Package (CodeHelper.Core.PlaceHolder) makes it easy to replace the placeholders with the value of the given object.

PreRequisites

• CodeHelper.Core.PlaceHolder

Example Text

Let's use an order confirmation email

Hi {CUSTOMERNAME},
<br />
Your order #{ORDERID} is confirmed and will be shipped out of our warehouse on {SHIPMENTDATE}
<br />
<b>Total Details</b><br />
Number of items: {NBOFITEMS}<br />
Total amount: {TOTALAMOUNT}
<br /><br />
Items:
{LISTOFITEMS}

The OrderInfo Class

Let's start with the class, containing the order info The only thing we need to do is

• Add using CodHelper.Core.PlaceHolder
• Add a Placeholder Attribute to the class properly

A Placeholder Attribute requires the placeholder value (string) used in the text and optional the format (string)

using CodeHelper.Core.PlaceHolder;

public class OrderInfo 
     {        
        [Placeholder("{ORDERID}")] 
        public Int64 ID { get; set; }

        public Int64 CustomerID { get; set; }

        [Placeholder("{CUSTOMERNAME}")] 
        public string CustomerName { get; set; } ="";

        [Placeholder("{SHIPMENTDATE}", "MMM dd, yyyy")]
        public DateTime DateShipmentDate { get; set; }

        public DateTime DateOrder{ get; set; }

        [Placeholder("{NBOFITEMS}", "#,##0")]
        public int NbShippedItems { get { return ShippedItemDescriptions.Count; } }

        [Placeholder("{TOTALAMOUNT}", "#,###,##0.00")]
        public double TotalAmount { get; set; }

        [Placeholder("{LISTOFITEMS}")]
        public List<string> ShippedItemDescriptions { get; set; } = new();
               
        public OrderInfo() { }         
    }

The Code

The replace string extension has the following parameters

• _order : object with the values
• false: Indicates if the text is an URL, if true, the empty parameters will be omitted, in our example it is not an URL, so false.
• FormatTypes.HTML: Text, HTML or Markdown (default: FormatTypes.TEXT)

using CodeHelper.Core.PlaceHolder;

//-- get the order info
OrderInfo _order = new() { ID = 99876, DateShipmentDate = DateTime.Today.AddDays(1) 
                                , TotalAmount = 1234.50
                                , CustomerID=333
                                , CustomerName ="CodeHelper"
                                , DateOrder= DateTime.Today };
    _order.ShippedItemDescriptions.Add("Product Description #1");
    _order.ShippedItemDescriptions.Add("Product Description # 2");
    _order.ShippedItemDescriptions.Add("Product Description # 3");

//-- Get The Confirmation Email Text
string emailBody = Resources.Translations.EmailConfirmOrder

//-- Replace the placeholder inside the text with the values of 
//-- the _order object
emailBody = emailBody.Replace(_order, false, FormatTypes.HTML);

Result:

The email is ready to send...

Hi CodeHelper,<br />
Your order #99876 is confirmed and will be shipped out of our warehouse on Sept 09, 2022
<br />
<b>Total Details</b><br />
Number of items: 3<br />
Total amount: 1,234.50
<br /><br />
Items:
<ul>
    <li>Product Description #1</li>
    <li>Product Description # 2</li>
    <li>Product Description # 3</li>
</ul>

Advantages

When the marketing team wants to change the confirmation email, add fields or translate to more languages, the code keeps working.

In case of adding a placeholder, simply add the attribute to the field.