---
title: "Inserting Documents Dynamically in C#"
---


{{% alert color="grey" %}}

## Purpose Summary

This page describes how to insert documents dynamically.

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You can insert contents of outer documents to your reports dynamically using `doc` tags. A `doc` tag denotes a placeholder within a template for a document to be inserted during runtime. 

Syntax of a `doc` tag is defined as follows.

{{< highlight csharp >}}
<<doc [document_expression]>>
{{< /highlight >}}

**Note** – A `doc` tag can be used almost anywhere in a template document except textboxes and charts.

An expression declared within a `doc` tag is used by the engine to load a document to be inserted during runtime. The expression must return a value of one of the following types:

- A byte array containing document data
- A [Stream](https://docs.microsoft.com/en-us/dotnet/api/system.io.stream?view=net-6.0) instance able to read document data
- An instance of the `Document` class
- A string containing a document URI, path, or Base64-encoded document data

While building a report, an expression declared within a `doc` tag is evaluated and its result is used to load a document which content replaces the `doc` tag then.

**Note** – If an expression declared within a `doc` tag returns a stream object, then the stream is closed by the engine as soon as a corresponding document is loaded.

By default, while inserting content of an outer document, the engine applies corresponding styles of a template document. This makes content of a result document look more consistent. However, you can keep source formatting for content being inserted by using a `sourceStyles` switch as shown in the following snippet.

{{< highlight csharp >}}
<<doc [document_expression] -sourceStyles>>
{{< /highlight >}}

The engine exhibits similar behavior when dealing with list numbering. By default, numbered lists from a template document are continued when their identifiers match those from a document being inserted. However, if numbering for content being inserted should be separated and kept as is, this can be done by applying a `sourceNumbering` switch as follows.

{{< highlight csharp >}}
<<doc [document_expression] -sourceNumbering>>
{{< /highlight >}}

Also, you can trim the last paragraph break from a document being inserted by using an `inline` switch. In particular, this feature is useful for a single-paragraph document being inserted, when it is necessary to put the document’s content within the same paragraph that contains a corresponding `doc` tag in order to apply the paragraph’s formatting such as list numbering. The following snippet shows the template syntax for this.

{{< highlight csharp >}}
<<doc [document_expression] -inline>>
{{< /highlight >}}

By default, a document being inserted is not checked against template syntax and is not populated with data. However, you can enable this by using a `build` switch as follows.

{{< highlight csharp >}}
<<doc [document_expression] -build>>
{{< /highlight >}}

When a `build` switch is used, the engine treats a document being inserted as a template that can access the following data available at the scope of a corresponding `doc` tag:

- Data sources
- Variables
- A contextual object (see “Using Contextual Object Member Access” for more information)
- Known external types (see “Setting up Known External Types” for more information)