Add Watermark into WordFile Using C#

Hi,

You can try this lib: https://www.e-iceblue.com/Download/download-word-for-net-free.html.

using System;
using System.Drawing;
using Spire.Doc;
using Spire.Doc.Documents;

namespace InsertWatermark
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //Create an object of Document class
            Document document = new Document();

            //Load a Word document from disk
            document.LoadFromFile(@"D:\Samples\Sample.docx");

            //Insert a text watermark
            InsertTextWatermark(document.Sections[0]);

            //Save the document
            document.SaveToFile("InsertTextWatermark.docx", FileFormat.Docx);
        }
        private static void InsertTextWatermark(Section section)
        {
            TextWatermark txtWatermark = new TextWatermark();
            txtWatermark.Text = "DO NOT COPY";
            txtWatermark.FontSize = 50;
            txtWatermark.Color = Color.Blue;
            txtWatermark.Layout = WatermarkLayout.Diagonal;
            section.Document.Watermark = txtWatermark;

        }
    }
}

Hi Gross Account,

Try below code

using System;
using Microsoft.Office.Interop.Word;
using Microsoft.Office.Core;

namespace Watermark.GUI
{
    public class Watermark
    {
        private Application wordApp;
        private Document doc;
        private string currentWatermarkText;

        public Watermark(Application wordApp, Document doc)
        {
            this.wordApp = wordApp;
            this.doc = doc;
        }

        public void AddCenteredTextWatermark(string watermarkText)
        {
            currentWatermarkText = watermarkText; // Store the current watermark text
            for (int pageIndex = 1; pageIndex <= doc.ComputeStatistics(WdStatistic.wdStatisticPages); pageIndex++)
            {
                AddWatermarkToPage(pageIndex);
            }
        }

        private void AddWatermarkToPage(int pageIndex)
        {
            Range pageRange = GetPageRange(doc, pageIndex);
            if (pageRange != null)
            {
                Shape watermark = doc.Shapes.AddTextEffect(
                    MsoPresetTextEffect.msoTextEffect1,
                    currentWatermarkText,
                    "Arial",
                    10,
                    MsoTriState.msoTrue,
                    MsoTriState.msoFalse,
                    0,
                    0,
                    pageRange
                );

                SetWatermarkProperties(watermark);
            }
        }

        private void SetWatermarkProperties(Shape watermark)
        {
            watermark.Fill.Visible = MsoTriState.msoTrue;
            watermark.Fill.Solid();
            watermark.Fill.ForeColor.RGB = (Int32)WdColor.wdColorGray20;
            watermark.Line.Visible = MsoTriState.msoFalse;
            watermark.WrapFormat.Type = WdWrapType.wdWrapBehind;
            watermark.Rotation = -45;

            watermark.Width = doc.PageSetup.PageWidth * 0.75f;
            watermark.Height = watermark.Width / 4;
            watermark.LockAspectRatio = MsoTriState.msoTrue;

            watermark.Left = (float)((doc.PageSetup.PageWidth - watermark.Width) / 2);
            watermark.Top = (float)((doc.PageSetup.PageHeight - watermark.Height) / 2);

            watermark.ZOrder(MsoZOrderCmd.msoSendToBack);
        }

        public void UpdateWatermark(string newWatermarkText)
        {
            currentWatermarkText = newWatermarkText; // Update the watermark text
            foreach (Shape shape in doc.Shapes)
            {
                if (shape.Type == MsoShapeType.msoTextEffect)
                {
                    shape.TextEffect.Text = currentWatermarkText; // Update text for all shapes
                }
            }
        }

        private Range GetPageRange(Document doc, int pageNumber)
        {
            object what = WdGoToItem.wdGoToPage;
            object which = WdGoToDirection.wdGoToAbsolute;
            object count = pageNumber;

            Range pageStart = doc.GoTo(ref what, ref which, ref count);
            object nextPage = pageNumber + 1;
            Range pageEnd = doc.GoTo(ref what, ref which, ref nextPage);
            pageEnd.SetRange(pageEnd.Start, pageEnd.Start);

            return doc.Range(pageStart.Start, pageEnd.Start);
        }
    }
}

Let me know if not working

Using This Code 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Office.Interop.Word;
using Microsoft.Office.Core;
using Shape = Microsoft.Office.Interop.Word.Shape;
 namespace Watermark.GUI
{
    namespace Watermark.GUI
    {
        public class Watermark
        {
            private Application wordApp;
            private Document doc;

            public Watermark(Application wordApp, Document doc)
            {
                this.wordApp = wordApp;
                this.doc = doc;
            }

            public void AddCenteredTextWatermark(string watermarkText)
            {
                for (int pageIndex = 1; pageIndex <= doc.ComputeStatistics(WdStatistic.wdStatisticPages); pageIndex++)
                {
                    // Create a Range object for each page
                    Range pageRange = GetPageRange(doc, pageIndex);
                    if (pageRange != null)
                    {
                        // Add the watermark to this page range
                        Shape watermark = doc.Shapes.AddTextEffect(
                         MsoPresetTextEffect.msoTextEffect1,
                         watermarkText,
                         "Arial",  // Font name
                         10,        // Font size
                         MsoTriState.msoTrue,   // Bold
                         MsoTriState.msoFalse,  // Italic
                         0,       // Left position (initial value)
                         0,       // Top position (initial value)
                         pageRange // Adding it to the range of the current page
                        );

                        // Set the watermark properties
                        watermark.Fill.Visible = MsoTriState.msoTrue;
                        watermark.Fill.Solid();
                        watermark.Fill.ForeColor.RGB = (Int32)WdColor.wdColorGray20; // Watermark color
                        watermark.Line.Visible = MsoTriState.msoFalse; // No border
                        watermark.WrapFormat.Type = WdWrapType.wdWrapBehind; // Behind text
                        watermark.Rotation = -45; // Rotation angle

                        // Set width and height relative to the page size
                        watermark.Width = doc.PageSetup.PageWidth * 0.75f; // Width as 60% of page width
                        watermark.Height = watermark.Width / 4; // Height relative to width to maintain aspect ratio
                        watermark.LockAspectRatio = MsoTriState.msoTrue;

                        // Center the watermark by adjusting Left and Top properties after setting width and height
                        watermark.Left = (float)((doc.PageSetup.PageWidth - watermark.Width) / 2); // Center horizontally
                        watermark.Top = (float)((doc.PageSetup.PageHeight - watermark.Height) / 2); // Center vertically

                        watermark.ZOrder(MsoZOrderCmd.msoSendToBack);
                    }
                }
            }
            private Range GetPageRange(Document doc, int pageNumber)
            {
                object what = WdGoToItem.wdGoToPage;
                object which = WdGoToDirection.wdGoToAbsolute;
                object count = pageNumber;

                // Move selection to the start of the desired page
                Range pageStart = doc.GoTo(ref what, ref which, ref count);

                // Move to the start of the next page to get end of range (or document end if it's the last page)
                object nextPage = pageNumber + 1;
                Range pageEnd = doc.GoTo(ref what, ref which, ref nextPage);
                pageEnd.SetRange(pageEnd.Start, pageEnd.Start);

                // Return a range spanning the current page
                return doc.Range(pageStart.Start, pageEnd.Start);
            }
        }
    }

}
I add Watermark. The method AddCenteredTextWatermark in the provided class adds a watermark as a text shape (Word Shape object) to each page of the Word document. Using This  if we remove the header, the watermark is not removed because it is not added to the header.That is fine.
Now I want For Edit if We Add Watermark Value In CustomeWatermark Option in Word then its editable .Now the watermark added with this code is editable but one page at a time. Not all edited at once. If you add a watermark value to Custom Watermark, you can edit the added watermark from there, and it will be edited in all pages. Or is there any other way so that I edit the watermark in one page and all pages are edited. But without adding to the header. Else when we do RemoveHeader the watermark is also removed.
if you know Another Solution then Provide it.

This Solution is Not Proper.

using System;
using Microsoft.Office.Interop.Word;

class Program
{
    static void Main()
    {
        Application wordApp = new Application();
        Document doc = wordApp.Documents.Open(@"C:\path\to\your\document.docx");
        wordApp.Visible = true;

        foreach (Section section in doc.Sections)
        {
            // Add a watermark
            Watermark watermark = section.Headers[WdHeaderFooterIndex.wdHeaderFooterPrimary].Shapes.AddTextEffect(
                Microsoft.Office.Core.MsoPresetTextEffect.msoTextEffect1,
                "Confidential",
                "Arial",
                36,
                Microsoft.Office.Core.MsoTriState.msoFalse,
                Microsoft.Office.Core.MsoTriState.msoFalse,
                0, 0);

            // Set the position and properties of the watermark
            watermark.WrapFormat.AllowOverlap = -1; // Allow overlap
            watermark.Left = (float)(doc.PageSetup.PageWidth / 2) - (watermark.Width / 2);
            watermark.Top = (float)(doc.PageSetup.PageHeight / 2) - (watermark.Height / 2);
            watermark.Fill.Transparency = 0.5f; // Set transparency
            watermark.TextEffect.NormalizedHeight = false;

            // Set the watermark to be editable
            watermark.TextEffect.Text = "Confidential"; // Editable text
        }

        doc.Save();
        doc.Close();
        wordApp.Quit();
    }
}
Watermark watermark = section.Headers[WdHeaderFooterIndex.wdHeaderFooterPrimary].Shapes.AddTextEffect(...)

Issue: will cause a compilation error because Watermark is not a valid type in the Microsoft Office Interop libraries. There is no such Watermark class or type available in the context of the Microsoft Office Interop library.

To achieve the desired functionality, the watermark should be added as a watermark object rather than a shape in the header. This can be accomplished by using the Watermark property of the PageSetup object. Below is the revised code that implements this solution:

using System;
using Microsoft.Office.Interop.Word;

class Program
{
    static void Main()
    {
        Application wordApp = new Application();
        Document doc = wordApp.Documents.Open(@"C:\path\to\your\document.docx");
        wordApp.Visible = true;

        foreach (Section section in doc.Sections)
        {
            // Add a watermark
            Watermark watermark = section.Headers[WdHeaderFooterIndex.wdHeaderFooterPrimary].Shapes.AddTextEffect(
                Microsoft.Office.Core.MsoPresetTextEffect.msoTextEffect1,
                "Confidential",
                "Arial",
                36,
                Microsoft.Office.Core.MsoTriState.msoFalse,
                Microsoft.Office.Core.MsoTriState.msoFalse,
                0, 0);

            // Set the position and properties of the watermark
            watermark.WrapFormat.AllowOverlap = -1; // Allow overlap
            watermark.Left = (float)(doc.PageSetup.PageWidth / 2) - (watermark.Width / 2);
            watermark.Top = (float)(doc.PageSetup.PageHeight / 2) - (watermark.Height / 2);
            watermark.Fill.Transparency = 0.5f; // Set transparency
            watermark.TextEffect.NormalizedHeight = false;

            // Set the watermark to be editable
            watermark.TextEffect.Text = "Confidential"; // Editable text
        }

        doc.Save();
        doc.Close();
        wordApp.Quit();
    }
}

using System;
using Microsoft.Office.Interop.Word;

class Program
{
    static void Main()
    {
        Application wordApp = new Application();
        Document doc = wordApp.Documents.Open(@"C:\path\to\your\document.docx");
        wordApp.Visible = true;

        foreach (Section section in doc.Sections)
        {
            // Add a watermark shape
            Shape watermark = section.Shapes.AddTextEffect(
                Microsoft.Office.Core.MsoPresetTextEffect.msoTextEffect1,
                "Confidential",
                "Arial",
                36,
                Microsoft.Office.Core.MsoTriState.msoFalse,
                Microsoft.Office.Core.MsoTriState.msoFalse,
                0, 0);

            // Set the position and properties of the watermark
            watermark.WrapFormat.AllowOverlap = -1; // Allow overlap
            watermark.Left = (float)(doc.PageSetup.PageWidth / 2) - (watermark.Width / 2);
            watermark.Top = (float)(doc.PageSetup.PageHeight / 2) - (watermark.Height / 2);
            watermark.Fill.Transparency = 0.5f; // Set transparency
            watermark.TextEffect.NormalizedHeight = false;
        }

        doc.Save();
        doc.Close();
        wordApp.Quit();
    }
}
Issue:-Add watermark to wordfile using this code which is good. But when the watermark is added using this code we open the created word file and click on the header to edit the watermark there is an option to remove the header in the header menu. When we click on the RemoveHeader option the watermark is also removed. It means that the watermark added to the header is not valid because it has been removed. Watermark like when we manually add it to word file from design menu is not added to header which is ok. And if we remove the header, the watermark is not removed because it is not added to the header. I want to add watermark like this by coding. So if the header is removed the watermark will not be removed. And second point watermarks should be editable. So if someone makes a change, it should be changed in all the pages of the word file.

To add a watermark to a Word document in C# without placing it in the header, you can utilize the Microsoft.Office.Interop.Word library. This approach allows you to insert a watermark as a shape, which can be edited and will reflect changes across all pages.

using System;
using Microsoft.Office.Interop.Word;

class Program
{
    static void Main()
    {
        Application wordApp = new Application();
        Document doc = wordApp.Documents.Open(@"C:\path\to\your\document.docx");
        wordApp.Visible = true;

        foreach (Section section in doc.Sections)
        {
            // Add a watermark shape
            Shape watermark = section.Shapes.AddTextEffect(
                Microsoft.Office.Core.MsoPresetTextEffect.msoTextEffect1,
                "Confidential",
                "Arial",
                36,
                Microsoft.Office.Core.MsoTriState.msoFalse,
                Microsoft.Office.Core.MsoTriState.msoFalse,
                0, 0);
            
            // Set the position and properties of the watermark
            watermark.WrapFormat.AllowOverlap = -1; // Allow overlap
            watermark.Left = (float)(doc.PageSetup.PageWidth / 2) - (watermark.Width / 2);
            watermark.Top = (float)(doc.PageSetup.PageHeight / 2) - (watermark.Height / 2);
            watermark.Fill.Transparency = 0.5f; // Set transparency
            watermark.TextEffect.NormalizedHeight = false;
        }

        doc.Save();
        doc.Close();
        wordApp.Quit();
    }
}

This code opens a Word document, iterates through its sections, and adds a watermark that is centered on each page. The watermark can be edited directly in Word, and any changes will be reflected across all instances. Ensure you have the necessary references to Microsoft.Office.Interop.Word and Microsoft.Office.Core in your project.