Private/Options/_ADValidationAndSave.ps1

function _ADValidationAndSave {
    if ($Options_CredentialsAlternateCheckBox.IsChecked) {
        if ($STTSettings.DCSettings.UseAlternateCredentials -eq $false) {
            if ($Options_CredentialsUsernameTextBox.Text) {
                $Username = $Options_CredentialsUsernameTextBox.Text
            }
            else {
                $MessageSplat = @{
                    MessageText  = 'Please provide a username.'
                    MessageIcon  = 'Hand'
                    ButtonType   = 'OK'
                    MessageTitle = 'Alternate AD Credentials Validation Error'
                }
                _ShowMessageBox @MessageSplat
            }
            if ($Options_CredentialsPasswordPasswordBox) {
                $Password = $Options_CredentialsPasswordPasswordBox.SecurePassword
            }
            else {
                $MessageSplat = @{
                    MessageText  = 'Please provide a password.'
                    MessageIcon  = 'Hand'
                    ButtonType   = 'OK'
                    MessageTitle = 'Alternate AD Credentials Validation Error'
                }
                _ShowMessageBox @MessageSplat
            }
            $Credential = New-Object System.Management.Automation.PSCredential ("$Username", $Password)
            $Credential | Export-Clixml -Path $env:APPDATA\LoganShell\Stored.xml
        }
    }
}