using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using Word = Microsoft.Office.Interop.Word;
using Office = Microsoft.Office.Core;
using wordTool = Microsoft.Office.Tools.Word;
using vsto = Microsoft.Office.Tools;

        private void button1_Click(object sender, EventArgs e)
        {
            Word.Document currentDocument = Globals.ThisAddIn.Application.ActiveDocument;
           
             if (currentDocument.Paragraphs != null &&
               currentDocument.Paragraphs.Count != 0)
             {                
                 // 在第一段文字前添加一個段落 
                 currentDocument.Paragraphs[1].Range.InsertParagraphBefore(); 
                 currentDocument.Paragraphs[1].Range.Select(); 
                 // 將Interop的Document對象轉(zhuǎn)化為VSTO中的Document對象 
                 wordTool.Document document = Globals.Factory.GetVstoObject(currentDocument);
                 // 添加DropDownList         
                 //wordTool.DropDownListContentControl dropdown = document.Controls.AddDropDownListContentControl(currentDocument.Paragraphs[1].Range, "MyContentControl");
                 //dropdown.PlaceholderText = "My DropdownList Test";
                 //dropdown.DropDownListEntries.Add("Test01", "01", 1);
                 //dropdown.DropDownListEntries.Add("Test02", "02", 2); 
                 //dropdown.DropDownListEntries.Add("Test03", "03", 3);

                 wordTool.RichTextContentControl d = document.Controls.AddRichTextContentControl(currentDocument.Paragraphs[1].Range, "合同管理");
               
                 d.Text = "合同文本";
                 d.Title = "合同文本";
                 //添加背景色
                 d.Range.Shading.BackgroundPatternColor = Word.WdColor.wdColorBlue;

                 //wordTool.RichTextContentControl dNO = document.Controls.AddRichTextContentControl(currentDocument.Paragraphs[1].Range, "合同編號");
                 //dNO.Text = "合同編號";
                 //dNO.Title = "合同編號";
                 ////添加背景色
                 //dNO.Range.Shading.BackgroundPatternColor = Word.WdColor.wdColorBlue;

                 //去掉背景色
                 //d.Range.Shading.BackgroundPatternColor = Word.WdColor.wdColorWhite;

                 //foreach (var ct in document.Controls.GetEnumerator)
                 //{
                 //    (wordTool.RichTextContentControl)
                 //}
             }
        }
        private System.Collections.Generic.List
         <Microsoft.Office.Tools.Word.RichTextContentControl> richTextControls;

      //遍歷控件賦值
        private void button2_Click(object sender, EventArgs e)
        {
            //if (Word.ContentControls<= 0)
            //    return;

            //richTextControls = new System.Collections.Generic.List
            //    <Microsoft.Office.Tools.Word.RichTextContentControl>();
            //int count = 0;

 微軟官方：https://msdn.microsoft.com/zh-cn/library/bb386200.aspx

注意：我這個是winform用戶控件