--- title: "PdfAnnotationCollection" canonical_url: "https://www.nutrient.io/api/csharp/editors/pdf/annotations/pdf-annotation-collection/" md_url: "https://www.nutrient.io/api/csharp/editors/pdf/annotations/pdf-annotation-collection.md" last_updated: "2026-10-08T08:55:57.709Z" description: "Represents a collection of annotations on a PDF page. Provides methods to access, add, and remove annotations." --- Represents a collection of annotations on a PDF page. Provides methods to access, add, and remove annotations. ```csharp using Nutrient; ``` The SDK creates this class through factory methods or other SDK objects. ## Collection access `PdfAnnotationCollection` implements `IReadOnlyList`, so you can index it, read its `Count`, and iterate it with `foreach`. ```csharp public PdfAnnotation this[int index] { get; } ``` Gets the element at the specified 0-based index. **Type:** [`PdfAnnotation`](/api/csharp/editors/pdf/annotations/pdf-annotation/) ## Properties ### Count ```csharp public int Count { get; } ``` The number of annotations in the collection. **Type:** `int` ## Methods ### AddCircle ```csharp public PdfCircleAnnotation AddCircle(float x, float y, float width, float height, string author, string contents) ``` Adds a circle (ellipse) annotation to this page. **Parameters** | Name | Type | Description | | ---------- | -------- | ----------------------------------------------------- | | `x` | `float` | The x coordinate of the bounding rectangle in points. | | `y` | `float` | The y coordinate of the bounding rectangle in points. | | `width` | `float` | The width of the bounding rectangle in points. | | `height` | `float` | The height of the bounding rectangle in points. | | `author` | `string` | The author of the annotation. | | `contents` | `string` | The text contents/comment for the annotation. | **Returns:** [`PdfCircleAnnotation`](/api/csharp/editors/pdf/annotations/pdf-circle-annotation/) - The newly created `PdfCircleAnnotation`. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ### AddFreeText ```csharp public PdfFreeTextAnnotation AddFreeText(float x, float y, float width, float height, string author, string contents, string fontName, float fontSize, Color fontColor) ``` Adds a free text annotation (text box) to this page. **Parameters** | Name | Type | Description | | ----------- | ----------------------------------- | ------------------------------------------- | | `x` | `float` | The x coordinate of the text box in points. | | `y` | `float` | The y coordinate of the text box in points. | | `width` | `float` | The width of the text box in points. | | `height` | `float` | The height of the text box in points. | | `author` | `string` | The author of the annotation. | | `contents` | `string` | The text contents to display. | | `fontName` | `string` | The name of the font to use. | | `fontSize` | `float` | The size of the font in points. | | `fontColor` | [`Color`](/api/csharp/types/color/) | The color of the text. | **Returns:** [`PdfFreeTextAnnotation`](/api/csharp/editors/pdf/annotations/pdf-free-text-annotation/) - The newly created `PdfFreeTextAnnotation`. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ### AddHighlight ```csharp public PdfHighlightAnnotation AddHighlight(float x, float y, float width, float height, string author, string contents) ``` Adds a highlight annotation to this page. **Parameters** | Name | Type | Description | | ---------- | -------- | ------------------------------------------------- | | `x` | `float` | The x coordinate of the highlight area in points. | | `y` | `float` | The y coordinate of the highlight area in points. | | `width` | `float` | The width of the highlight area in points. | | `height` | `float` | The height of the highlight area in points. | | `author` | `string` | The author of the annotation. | | `contents` | `string` | The text contents/comment for the annotation. | **Returns:** [`PdfHighlightAnnotation`](/api/csharp/editors/pdf/annotations/pdf-highlight-annotation/) - The newly created `PdfHighlightAnnotation`. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ### AddLine ```csharp public PdfLineAnnotation AddLine(float startX, float startY, float endX, float endY, string author, string contents) ``` Adds a line annotation to this page. **Parameters** | Name | Type | Description | | ---------- | -------- | ----------------------------------------------- | | `startX` | `float` | X coordinate of the line start point in points. | | `startY` | `float` | Y coordinate of the line start point in points. | | `endX` | `float` | X coordinate of the line end point in points. | | `endY` | `float` | Y coordinate of the line end point in points. | | `author` | `string` | The author of the annotation. | | `contents` | `string` | The text contents/comment for the annotation. | **Returns:** [`PdfLineAnnotation`](/api/csharp/editors/pdf/annotations/pdf-line-annotation/) - The newly created `PdfLineAnnotation`. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ### AddLink ```csharp public PdfLinkAnnotation AddLink(float x, float y, float width, float height) ``` Adds an empty link annotation to this page. Use the returned annotation's `URI` property or `SetDestination` method to configure the link target. **Parameters** | Name | Type | Description | | -------- | ------- | -------------------------------------------- | | `x` | `float` | The x coordinate of the link area in points. | | `y` | `float` | The y coordinate of the link area in points. | | `width` | `float` | The width of the link area in points. | | `height` | `float` | The height of the link area in points. | **Returns:** [`PdfLinkAnnotation`](/api/csharp/editors/pdf/annotations/pdf-link-annotation/) - The newly created `PdfLinkAnnotation`. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ### AddRedact ```csharp public PdfRedactAnnotation AddRedact(float x, float y, float width, float height) ``` Adds a redaction annotation to this page. The annotation marks content for redaction but does not apply the redaction until `ApplyRedactions` is called. **Parameters** | Name | Type | Description | | -------- | ------- | ------------------------------------------------- | | `x` | `float` | The x coordinate of the redaction area in points. | | `y` | `float` | The y coordinate of the redaction area in points. | | `width` | `float` | The width of the redaction area in points. | | `height` | `float` | The height of the redaction area in points. | **Returns:** [`PdfRedactAnnotation`](/api/csharp/editors/pdf/annotations/pdf-redact-annotation/) - The newly created `PdfRedactAnnotation`. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ### AddSquare ```csharp public PdfSquareAnnotation AddSquare(float x, float y, float width, float height, string author, string contents) ``` Adds a square (rectangle) annotation to this page. **Parameters** | Name | Type | Description | | ---------- | -------- | --------------------------------------------- | | `x` | `float` | The x coordinate of the rectangle in points. | | `y` | `float` | The y coordinate of the rectangle in points. | | `width` | `float` | The width of the rectangle in points. | | `height` | `float` | The height of the rectangle in points. | | `author` | `string` | The author of the annotation. | | `contents` | `string` | The text contents/comment for the annotation. | **Returns:** [`PdfSquareAnnotation`](/api/csharp/editors/pdf/annotations/pdf-square-annotation/) - The newly created `PdfSquareAnnotation`. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ### AddSquiggly ```csharp public PdfSquigglyAnnotation AddSquiggly(float x, float y, float width, float height, string author, string contents) ``` Adds a squiggly underline annotation to this page. **Parameters** | Name | Type | Description | | ---------- | -------- | ------------------------------------------------ | | `x` | `float` | The x coordinate of the squiggly area in points. | | `y` | `float` | The y coordinate of the squiggly area in points. | | `width` | `float` | The width of the squiggly area in points. | | `height` | `float` | The height of the squiggly area in points. | | `author` | `string` | The author of the annotation. | | `contents` | `string` | The text contents/comment for the annotation. | **Returns:** [`PdfSquigglyAnnotation`](/api/csharp/editors/pdf/annotations/pdf-squiggly-annotation/) - The newly created `PdfSquigglyAnnotation`. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ### AddStamp ```csharp public PdfStampAnnotation AddStamp(float x, float y, float width, float height, string title, string contents) ``` Adds a rubber stamp annotation to this page. **Parameters** | Name | Type | Description | | ---------- | -------- | ---------------------------------------- | | `x` | `float` | The x coordinate of the stamp in points. | | `y` | `float` | The y coordinate of the stamp in points. | | `width` | `float` | The width of the stamp in points. | | `height` | `float` | The height of the stamp in points. | | `title` | `string` | The title of the annotation. | | `contents` | `string` | The text contents of the annotation. | **Returns:** [`PdfStampAnnotation`](/api/csharp/editors/pdf/annotations/pdf-stamp-annotation/) - The newly created `PdfStampAnnotation`. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ### AddStickyNote ```csharp public PdfTextAnnotation AddStickyNote(float x, float y, string author, string subject, string contents) ``` Adds a sticky note (text) annotation to this page. **Parameters** | Name | Type | Description | | ---------- | -------- | --------------------------------------------- | | `x` | `float` | The x coordinate of the annotation in points. | | `y` | `float` | The y coordinate of the annotation in points. | | `author` | `string` | The author of the annotation. | | `subject` | `string` | The subject of the annotation. | | `contents` | `string` | The text contents of the annotation. | **Returns:** [`PdfTextAnnotation`](/api/csharp/editors/pdf/annotations/pdf-text-annotation/) - The newly created `PdfTextAnnotation`. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ### AddStrikeOut ```csharp public PdfStrikeOutAnnotation AddStrikeOut(float x, float y, float width, float height, string author, string contents) ``` Adds a strikeout annotation to this page. **Parameters** | Name | Type | Description | | ---------- | -------- | ------------------------------------------------- | | `x` | `float` | The x coordinate of the strikeout area in points. | | `y` | `float` | The y coordinate of the strikeout area in points. | | `width` | `float` | The width of the strikeout area in points. | | `height` | `float` | The height of the strikeout area in points. | | `author` | `string` | The author of the annotation. | | `contents` | `string` | The text contents/comment for the annotation. | **Returns:** [`PdfStrikeOutAnnotation`](/api/csharp/editors/pdf/annotations/pdf-strike-out-annotation/) - The newly created `PdfStrikeOutAnnotation`. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ### AddUnderline ```csharp public PdfUnderlineAnnotation AddUnderline(float x, float y, float width, float height, string author, string contents) ``` Adds an underline annotation to this page. **Parameters** | Name | Type | Description | | ---------- | -------- | ------------------------------------------------- | | `x` | `float` | The x coordinate of the underline area in points. | | `y` | `float` | The y coordinate of the underline area in points. | | `width` | `float` | The width of the underline area in points. | | `height` | `float` | The height of the underline area in points. | | `author` | `string` | The author of the annotation. | | `contents` | `string` | The text contents/comment for the annotation. | **Returns:** [`PdfUnderlineAnnotation`](/api/csharp/editors/pdf/annotations/pdf-underline-annotation/) - The newly created `PdfUnderlineAnnotation`. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ### RemoveAt ```csharp public void RemoveAt(int index) ``` Removes the annotation at the specified index. **Parameters** | Name | Type | Description | | ------- | ----- | ---------------------------------------------- | | `index` | `int` | The 0-based index of the annotation to remove. | **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when no page is loaded. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the index is out of range. **Throws:** [`NutrientException`](/api/csharp/exceptions/nutrient-exception/) - Thrown when the operation fails. ## Resource management ```csharp public void Dispose() ``` `PdfAnnotationCollection` implements `IDisposable`. Call `Dispose()` or use a C# `using` declaration to release its native handle right away. If you don't, the handle is released when the object is garbage collected. --- ## Related pages - [Annotations](/api/csharp/editors/pdf/annotations.md) - [Pdf Annotation](/api/csharp/editors/pdf/annotations/pdf-annotation.md) - [Pdf Circle Annotation](/api/csharp/editors/pdf/annotations/pdf-circle-annotation.md) - [Pdf Free Text Annotation](/api/csharp/editors/pdf/annotations/pdf-free-text-annotation.md) - [Pdf Highlight Annotation](/api/csharp/editors/pdf/annotations/pdf-highlight-annotation.md) - [Pdf Line Annotation](/api/csharp/editors/pdf/annotations/pdf-line-annotation.md) - [Pdf Link Annotation](/api/csharp/editors/pdf/annotations/pdf-link-annotation.md) - [Pdf Markup Annotation](/api/csharp/editors/pdf/annotations/pdf-markup-annotation.md) - [Pdf Redact Annotation](/api/csharp/editors/pdf/annotations/pdf-redact-annotation.md) - [Pdf Shape Annotation](/api/csharp/editors/pdf/annotations/pdf-shape-annotation.md) - [Pdf Square Annotation](/api/csharp/editors/pdf/annotations/pdf-square-annotation.md) - [Pdf Squiggly Annotation](/api/csharp/editors/pdf/annotations/pdf-squiggly-annotation.md) - [Pdf Stamp Annotation](/api/csharp/editors/pdf/annotations/pdf-stamp-annotation.md) - [Pdf Strike Out Annotation](/api/csharp/editors/pdf/annotations/pdf-strike-out-annotation.md) - [Pdf Text Annotation](/api/csharp/editors/pdf/annotations/pdf-text-annotation.md) - [Pdf Underline Annotation](/api/csharp/editors/pdf/annotations/pdf-underline-annotation.md) - [Pdf Widget Annotation](/api/csharp/editors/pdf/annotations/pdf-widget-annotation.md)