How to Create Add-Ins Using VSTO in MS-Word

Step 2. Create Ribbon

Right-click on your project's Solution Explorer click on "Add New Item" and select "Ribbon (Visual Designer)" in the item list.

Give the name of your Ribbon Control and click on the "Add" button. You will see that in the following screenshot.

Step 3. Add Office Ribbon Control from ToolBox

Once you have added your Ribbon Control, open the ToolBox from Visual Studio. You will see various tools in the ToolBox. There is a default Ribbon Group control available on your Ribbon as shown in the following screenshot.

Choose "Label control" from the Office Ribbon Control from the Toolbox and drag and drop this label control into the group control of your Ribbon. Give an appropriate name for your controls.

Step 4. Add a Windows Forms formin the Office Ribbon Control

We need to show the current time while clicking on the ShowTime button. So, here I am using a Windows Forms form to show the current time.

Right-click on your project and select "Add new item" from the menu. Select "Windows Form".

Step 5. Once you have added a Windows Forms form to your project, click on the Windows Forms form and add two labels. The first one is a caption label and the second label shows the current time value. Provide a meaningful full name for the label and form control. You will see that in the following screenshot.

On your Windows Forms form, please add code to display the current time in the form load event.

lblCurrentTimeVal.Text = DateTime.Now.ToShortTimeString();

Step 6. Double-click on your Ribbon control button, and you will get a click event of the ribbon control. Write the following code to show our Windows Forms form.

private void btnClock_Click(object sender, RibbonControlEventArgs e)
{
    frmShowTime frmTime = new frmShowTime();
    frmTime.Show();
}

Step 7. Build and run your Add-Ins project. You will see a new ribbon add-in with "MyFirstAdd Ins" in your Word document as shown in the following screenshot.

Step 8. Click on the "ShowTime" Ribbon button. You will see the current time in our Windows Forms form as shown in the following screenshot.

Reference Link: http://msdn.microsoft.com/en-us/library/d2tx7z6d(v=vs.100).aspx