Checking for a Previous Instance

Checking for a Previous Instance

When working in Windows, it is very easy to lose a minimized icon onthe desktop. Or you may forget you have an application running and tryto open it again from the Program Manager. There are times, however, whenyou don’t want to run two separate instances of an application. To preventthis you can use the built-in system object App to determine whether anotherinstance of an application is running. Here’s a routine you can use inyour Form_Load() or Main() procedures to do this:

 Sub Form_Load () Dim sCaption As String If App.PrevInstance Then sCaption = Me.Caption MsgBox "Another Instance Is Already Running" Me.Caption = "Different Caption" AppActivate sCaption SendKeys "% R", True Unload Me End If End Sub 

Checking the App.PrevInstance property to see if it contains aTrue value tells you if another instance is running. If it is, inform theuser, then activate the first instance prior to shutting down the second.You can activate any application that is currently running by using theAppActivate statement and passing the text that appears in the application’stitle bar. This technique requires that the current instance has the same captionas the one you want to activate, so you’ll need to change the current titleof the main window and then call AppActivate with the caption of the application.Call the statement SendKeys to tell the other instance to restore itselfto a normal window state. The “% R” string passed to the SendKeysstatement tells the application to invoke the control menu and select theRestore option. The code to check for multiple instances should be placed in the Main()or Form_Load() of your start-up form. This technique will not work if youincorporate information within the caption at run time, such as the currentdata-file name.

Share the Post:
XDR solutions

The Benefits of Using XDR Solutions

Cybercriminals constantly adapt their strategies, developing newer, more powerful, and intelligent ways to attack your network. Since security professionals must innovate as well, more conventional endpoint detection solutions have evolved

AI is revolutionizing fraud detection

How AI is Revolutionizing Fraud Detection

Artificial intelligence – commonly known as AI – means a form of technology with multiple uses. As a result, it has become extremely valuable to a number of businesses across

AI innovation

Companies Leading AI Innovation in 2023

Artificial intelligence (AI) has been transforming industries and revolutionizing business operations. AI’s potential to enhance efficiency and productivity has become crucial to many businesses. As we move into 2023, several

data fivetran pricing

Fivetran Pricing Explained

One of the biggest trends of the 21st century is the massive surge in analytics. Analytics is the process of utilizing data to drive future decision-making. With so much of

kubernetes logging

Kubernetes Logging: What You Need to Know

Kubernetes from Google is one of the most popular open-source and free container management solutions made to make managing and deploying applications easier. It has a solid architecture that makes

ransomware cyber attack

Why Is Ransomware Such a Major Threat?

One of the most significant cyber threats faced by modern organizations is a ransomware attack. Ransomware attacks have grown in both sophistication and frequency over the past few years, forcing

data dictionary

Tools You Need to Make a Data Dictionary

Data dictionaries are crucial for organizations of all sizes that deal with large amounts of data. they are centralized repositories of all the data in organizations, including metadata such as