Скачать или смотреть How to Easily Update DataGridView Data in C# WinForms from Another Form

Discover how to modify a SQL query and update your DataGridView in a C# WinForms application from a different form effectively.
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This video is based on the question https://stackoverflow.com/q/65286619/ asked by the user 'Pierre_CM' ( https://stackoverflow.com/u/13733229/ ) and on the answer https://stackoverflow.com/a/72727218/ provided by the user 'Ricardo Rodrigues' ( https://stackoverflow.com/u/10675898/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Updating DataGridView Data from Another Form in C# WinForms

Handling multiple forms in a C# WinForms application can often be a challenging task, especially when you need to update a visual component like a DataGridView from another form. In this guide, we will explore a common scenario where you want to change the SQL query that feeds your DataGridView based on user input from another form. We'll break down the solution step by step to help you efficiently manage such requirements in your application.

The Problem

Imagine you have an application with two forms: Form1 and Form2. In Form1, you have a DataGridView that displays results from a SQL query, which is dynamically generated based on selections made from various list boxes. At some point, you want to open Form2, allow the user to manipulate the data (like dragging and dropping values among list boxes), and then update the DataGridView in Form1 based on the selections from Form2. This leads us to some key questions:

How can data from Form2 effectively influence content in Form1?

Should you update Form1's SQL query directly from Form2?

Is it better to create a new instance of Form1 or maintain the same instance?

The Solution

Step 1: Opening and Referencing Form1 from Form2

When you open Form2 from Form1, you will want to pass a reference of Form1 to Form2. You can do this in the button click event handler in Form1 where you trigger Form2:

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In the constructor of Form2, you will save this reference to a variable:

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Step 2: Creating an Update Method in Form1

In Form1, create a method that will handle the updates needed for the DataGridView. This method can be called UpdateStuff and should take parameters which you deem necessary for the update:

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Step 3: Updating Data from Form2

Now, in Form2, after the user makes their selections and clicks a button to confirm, you can call the UpdateStuff method of Form1 to push changes to the DataGridView:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By following these steps, you can effectively manage updates in a WinForms application where multiple forms interact with a shared data source. The key takeaway is to maintain a reference to Form1 in Form2 and employ a public method that allows updates to occur. This method consolidates the logic for altering the SQL query and subsequently updating the DataGridView, all while keeping your forms loosely coupled yet functional.

If you implement these best practices, your Windows Forms application will become more maintainable and easier to understand, ensuring a smooth user experience as they navigate through your program.