Resolving DataGridView Cell Formatting Issues: Keeping Rows Color-Coded Based on Values

Описание: Discover how to effectively format rows in a DataGridView based on cell values in C# . Your DataGridView will only show green for rows containing data while leaving others untouched.
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This video is based on the question https://stackoverflow.com/q/63022647/ asked by the user 'feraldayor' ( https://stackoverflow.com/u/13972037/ ) and on the answer https://stackoverflow.com/a/63045304/ provided by the user 'JohnG' ( https://stackoverflow.com/u/6842716/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Problem with Cell Formatting in DataGridView

When working with a DataGridView in C# , it often becomes necessary to format rows based on the values contained in specific cells. In this case, we're addressing a common issue: changing the row's color to signify whether a value exists or is absent in a specific column.

The Issue at Hand

You have a DataGridView populated with data, and your goal is to highlight rows in green if a certain column (in this case, column 11) contains a value. Conversely, if the cell is empty, you want no formatting applied. This seems simple, but an issue arises when the formatting persists incorrectly, causing other cells or rows to be improperly colored.

For instance, if the cell in column 11 of row 0 has a value, it colors that row green, but after clearing the value, the row remains green instead of reverting back to its original state.

Solution to the Coloring Conflict

To ensure that the DataGridView behaves as expected, we need to enhance the CellFormatting event handler. The current logic only handles the condition for coloring the row green but fails to reset the color when the cell is empty.

Updated Cell Formatting Code

Here's a refined version of the method implementation that checks if the cell is empty and applies the necessary color modifications.

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

Breakdown of the Code

Column Check: The code checks if the formatting event is being called for column 11.

Value Check: It uses String.IsNullOrEmpty to determine whether the cell in column 11 has content.

Color Application:

If there is a value, it sets the background color to green.

If the cell is empty, it resets the background color back to white.

Why This Works

The key issue was that the previous code didn't reset the row’s background color when the cell was empty. By adding a condition to set the color back to white, the expected behavior is achieved. This solution allows for dynamic updates to the DataGridView—ensuring that formatting accurately reflects the data presented in each cell.

Conclusion

By implementing these changes into your CellFormatting event, your DataGridView will accurately reflect changes in the data—highlighting rows with values while resetting colors for empty cells. With these adjustments, your UI will remain clean and user-friendly, visualizing important data where necessary.

If you have further questions or would like more assistance with your implementation, feel free to reach out!