Private/Options/_ADValidationAndSave.ps1

function _ADValidationAndSave {
    if ($Options_CredentialsAlternateCheckBox.IsChecked) {
        if ($Options_CredentialsUsernameTextBox.Text) {
            $Username = $Options_CredentialsUsernameTextBox.Text
        }
        else {
            $MessageSplat = @{
                MessageText  = 'Please provide a username.'
                MessageIcon  = 'Hand'
                ButtonType   = 'OK'
                MessageTitle = 'Error'
            }
            _ShowMessageBox @MessageSplat
        }
        if ($Options_CredentialsPasswordPasswordBox) {
            $Password = $Options_CredentialsPasswordPasswordBox.SecurePassword
        }
        else {
            $MessageSplat = @{
                MessageText  = 'Please provide a password.'
                MessageIcon  = 'Hand'
                ButtonType   = 'OK'
                MessageTitle = 'Error'
            }
            _ShowMessageBox @MessageSplat
        }
    }

    $Credential = New-Object System.Management.Automation.PSCredential ("$Username", $Password)
    $Credential | Export-Clixml -Path $env:APPDATA\LoganShell\Stored.xml
}