PictureBox.Load Method

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Displays an image in the PictureBox.

Overloads

Load()	Displays the image specified by the ImageLocation property of the PictureBox.
Load(String)	Sets the ImageLocation to the specified URL and displays the image indicated.

Load()

Displays the image specified by the ImageLocation property of the PictureBox.

public:
 void Load();

public void Load ();

member this.Load : unit -> unit

Public Sub Load ()

Exceptions

InvalidOperationException

ImageLocation is null or an empty string.

Remarks

Starting with .NET 8, the behavior of how a PictureBox control loads a remote image changed. By default, the System.Net.ServicePointManager.CheckCertificateRevocationList property is set to true before a remote image is downloaded through WebClient. This setting ensures that servers with certificates have those certificates checked against the certificate authority revocation list (CRL) as part of the validation process.

Warning

As soon as a remote image is loaded, CheckCertificateRevocationList is changed to true for the lifetime of the app. You can revert back to false manually if required, but as soon as another remote image is loaded, CheckCertificateRevocationList is set to true.

A previously working remote resource might fail to load when the locally cached CRL is out-of-date and an update can't be retrieved. This can happen when the network the app is running on is restricted and the CRL location isn't on the allowlist.

It's also possible that the delay in checking the CRL negatively affects the app's ability to function.

You can opt out of this behavior by setting the System.Windows.Forms.ServicePointManagerCheckCrl option for the app, in one of the following ways:

• Set the property to false in the [app].runtimeconfig.json configuration file:

  {
    "configProperties": {
      "System.Windows.Forms.ServicePointManagerCheckCrl": false
    }
  }
  

• Add a <RuntimeHostConfigurationOption> item in the project file to disable it:

  <ItemGroup>
    <RuntimeHostConfigurationOption Include="System.Windows.Forms.ServicePointManagerCheckCrl" Value="false" />
  </ItemGroup>
  

See also

• LoadAsync

Load(String)

Sets the ImageLocation to the specified URL and displays the image indicated.

public:
 void Load(System::String ^ url);

public void Load (string url);

member this.Load : string -> unit

Public Sub Load (url As String)

Parameters

url

String

The path for the image to display in the PictureBox.

Exceptions

InvalidOperationException

url is null or an empty string.

WebException

url refers to an image on the Web that cannot be accessed.

ArgumentException

url refers to a file that is not an image.

FileNotFoundException

url refers to a file that does not exist.

Remarks

If the url parameter indicates a local file, the recommended format is a local file path. For example, an image file named myPicture.jpg located at c:\ would be accessed by passing c:\myPicture.jpg for the url parameter. A full path, such as http://www.contoso.com/path/images/image.jpg, or a relative path, such as ./images/image.jpg, can be used. If a relative path is used, it will be considered relative to the working directory. A call to the Load method sets the ImageLocation property to the value of the url parameter.

Load behavior changes

Starting with .NET 8, the behavior of how a PictureBox control loads a remote image changed. By default, the System.Net.ServicePointManager.CheckCertificateRevocationList property is set to true before a remote image is downloaded through WebClient. This setting ensures that servers with certificates have those certificates checked against the certificate authority revocation list (CRL) as part of the validation process.

Warning

As soon as a remote image is loaded, CheckCertificateRevocationList is changed to true for the lifetime of the app. You can revert back to false manually if required, but as soon as another remote image is loaded, CheckCertificateRevocationList is set to true.

A previously working remote resource might fail to load when the locally cached CRL is out-of-date and an update can't be retrieved. This can happen when the network the app is running on is restricted and the CRL location isn't on the allowlist.

It's also possible that the delay in checking the CRL negatively affects the app's ability to function.

You can opt out of this behavior by setting the System.Windows.Forms.ServicePointManagerCheckCrl option for the app, in one of the following ways:

• Set the property to false in the [app].runtimeconfig.json configuration file:

  {
    "configProperties": {
      "System.Windows.Forms.ServicePointManagerCheckCrl": false
    }
  }
  

• Add a <RuntimeHostConfigurationOption> item in the project file to disable it:

  <ItemGroup>
    <RuntimeHostConfigurationOption Include="System.Windows.Forms.ServicePointManagerCheckCrl" Value="false" />
  </ItemGroup>
  

See also

• ImageLocation