In addition to the integrated validation, RadUpload lets you perform your own custom validation using the server-side ValidatingFile event. By using this event, you can use your own custom validation logic and override the integrated validation if needed.

To validate a file in the ValidatingFile event handler, set the IsValid property of the event arguments to true or false, in order to indicate whether the file is valid. Then set the SkipInternalValidation property of the event arguments to true to bypass the default validation on any files you have validated using the event handler.

As with integrated validation, valid files can be accessed using the UploadedFiles property and invalid files using the InvalidFiles property.

The following example illustrates using custom validation to bypass the integrated size validation for zip files. The rest of the uploaded files are validated against the declared maximum file size:

CopyASPX

<telerik:radupload id="RadUpload1" runat="server" maxfilesize="1000000" targetfolder="~/MyFiles"
    onvalidatingfile="RadUpload1_ValidatingFile"></telerik:radupload>
<asp:Button runat="server" ID="Button1" Text="Submit" />

• C#
• VB.NET

CopyC#

     

using Telerik.Web.UI;
using Telerik.Web.UI.Upload;...

    private void RadUpload1_ValidatingFile( object sender, ValidateFileEventArgs e) 
    {  
        // check only the zip files  
        if (e.UploadedFile.GetExtension().ToLower() == ".zip")  
        {    
            //define the maximum file size to be 2000000 bytes    
            int maxZipFileSize = 2000000;    
            //if the zip file size exceeds 2000000 bytes mark it as invalid    
            if (e.UploadedFile.ContentLength > maxZipFileSize)    
            {       
                e.IsValid = false;
            }    
            // zip files must not be validated for file size by the internal validator    
            e.SkipInternalValidation = true;
        }
    }

CopyVB.NET

     

Imports Telerik.Web.UI
Imports Telerik.Web.UI.Upload...

    Private Sub RadUpload1_ValidatingFile(ByVal sender As Object, ByVal e As ValidateFileEventArgs) Handles RadUpload1.ValidatingFile

        ' check only the zip files  
        If e.UploadedFile.GetExtension.ToLower = ".zip" Then
            'define the maximum file size to be 2000000 bytes    
            Dim maxZipFileSize As Integer = 2000000
            'if the zip file size exceeds 2000000 mark it as invalid
            If e.UploadedFile.ContentLength > maxZipFileSize Then
                e.IsValid = False
            End If
            'The zip files must not be validated for file size by the internal validator    
            e.SkipInternalValidation = True
        End If

    End Sub

Note
For an example of custom validation that checks the content of the uploaded file, see ValidatingFile.