ProgressBar.PerformStep Method ()

 

Advances the current position of the progress bar by the amount of the Step property.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

public void PerformStep()

Exception Condition
InvalidOperationException

Style is set to Marquee.

The PerformStep method increments the value of the progress bar by the amount specified by the Step property. You can use the Step property to specify the amount that each completed task in an operation changes the value of the progress bar. For example, if you are copying a group of files, you might want to set the value of the Step property to 1 and the value of the Maximum property to the total number of files to copy. When each file is copied, you can call the PerformStep method to increment the progress bar by the value of the Step property. If you want to have more flexible control of the value of the progress bar, you can use the Increment method or set the value of the Value property directly.

The Value property specifies the current position of the ProgressBar. If, after calling the PerformStep method, the Value property is greater than the value of the Maximum property, the Value property remains at the value of the Maximum property. If, after calling the PerformStep method with a negative value specified in Step, the Value property is less than the value of the Minimum property, the Value property remains at the value of the Minimum property.

Because a ProgressBar object whose style is set to Marquee displays a continuously scrolling bar instead of its Value, calling PerformStep is unnecessary and will raise an InvalidOperationException.

The following code example uses a ProgressBar control to display the progress of a file copy operation. The example uses the Minimum and Maximum properties to specify a range for the ProgressBar that is equivalent to the number of files to copy. The code also uses the Step property with the PerformStep method to increment the value of the ProgressBar as a file is copied. This example requires that you have a ProgressBar control created called pBar1 that is created within a Form, and that there is a method created called CopyFile (that returns a Boolean value indicating the file copy operation was completed successfully) that performs the file copy operation. The code also requires that an array of strings containing the files to copy is created and passed to the CopyWithProgress method defined in the example, and that the method is called from another method or event in the Form.

private void CopyWithProgress(string[] filenames)
{
	// Display the ProgressBar control.
	pBar1.Visible = true;
	// Set Minimum to 1 to represent the first file being copied.
	pBar1.Minimum = 1;
	// Set Maximum to the total number of files to copy.
	pBar1.Maximum = filenames.Length;
	// Set the initial value of the ProgressBar.
	pBar1.Value = 1;
	// Set the Step property to a value of 1 to represent each file being copied.
	pBar1.Step = 1;

	// Loop through all files to copy.
	for (int x = 1; x <= filenames.Length; x++)
	{
		// Copy the file and increment the ProgressBar if successful.
		if(CopyFile(filenames[x-1]) == true)
		{
			// Perform the increment on the ProgressBar.
			pBar1.PerformStep();
		}
	}
}

.NET Framework
Available since 1.1
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