UWP C#报错：无法将string转换为byte[]/DateTime/bool 求助

Hey there, let's work through this type mismatch issue you're hitting. Since all your input fields are TextBoxes (which output strings), but your WCF service expects DateTime, byte[], and bool types, we need to safely convert each string input to the correct type before calling RegisterUserAsync. Here's how to handle each case:

1. Converting String to DateTime (DateOfBirthBox.Text) #

First, you'll want to validate and parse the date string into a DateTime object. Using DateTime.TryParseExact is safer than plain Parse because it lets you enforce a specific date format (e.g., yyyy-MM-dd, MM/dd/yyyy) that matches what your users are expected to input. This avoids unexpected failures from inconsistent date formats.

DateTime dateOfBirth;
if (!DateTime.TryParseExact(DateOfBirthBox.Text, "yyyy-MM-dd", CultureInfo.InvariantCulture, DateTimeStyles.None, out dateOfBirth))
{
    // Show error to user: "Please enter a valid date in YYYY-MM-DD format"
    var dialog = new MessageDialog("Please enter a valid date in YYYY-MM-DD format.");
    await dialog.ShowAsync();
    return;
}

2. Converting String to bool (EULicenseBox.Text, NonEULicenseBox.Text) #

Assuming your users are entering values like "true"/"false", "yes"/"no", or "1"/"0" for these boolean fields, you can parse them to bool with validation. For example:

bool euLicenseAccepted;
if (!bool.TryParse(EULicenseBox.Text, out euLicenseAccepted))
{
    // Fallback logic if parsing fails, e.g., check for "yes"/"no"
    euLicenseAccepted = EULicenseBox.Text.Equals("yes", StringComparison.OrdinalIgnoreCase);
}

bool nonEuLicenseAccepted;
if (!bool.TryParse(NonEULicenseBox.Text, out nonEuLicenseAccepted))
{
    nonEuLicenseAccepted = NonEULicenseBox.Text.Equals("yes", StringComparison.OrdinalIgnoreCase);
}

Pro tip: If these are "accept terms" style fields, consider using a CheckBox instead of a TextBox—this avoids string parsing entirely and gives a better user experience!

3. Converting String to byte[] #

Since you can't directly input a byte array into a TextBox, I'm assuming you're storing the byte data as a Base64-encoded string (a common approach for transmitting binary data as text). To convert this back to a byte[]:

byte[] euLicenseBytes = null;
try
{
    // Replace with the TextBox that holds your Base64-encoded byte array
    euLicenseBytes = Convert.FromBase64String(EULicenseBox.Text);
}
catch (FormatException)
{
    var dialog = new MessageDialog("Invalid license data. Please enter a valid Base64 string.");
    await dialog.ShowAsync();
    return;
}

Note: If the byte[] field is tied to a file (like a license file), you might want to replace the TextBox with a file picker control to get the byte array directly, instead of relying on manual Base64 input.

Putting It All Together #

Here's your updated code with all conversions and validation:

// Validate and convert each field
DateTime dateOfBirth;
if (!DateTime.TryParseExact(DateOfBirthBox.Text, "yyyy-MM-dd", CultureInfo.InvariantCulture, DateTimeStyles.None, out dateOfBirth))
{
    var dialog = new MessageDialog("Please enter a valid date in YYYY-MM-DD format.");
    await dialog.ShowAsync();
    return;
}

bool euLicenseAccepted;
if (!bool.TryParse(EULicenseBox.Text, out euLicenseAccepted))
{
    euLicenseAccepted = EULicenseBox.Text.Equals("yes", StringComparison.OrdinalIgnoreCase);
}

bool nonEuLicenseAccepted;
if (!bool.TryParse(NonEULicenseBox.Text, out nonEuLicenseAccepted))
{
    nonEuLicenseAccepted = NonEULicenseBox.Text.Equals("yes", StringComparison.OrdinalIgnoreCase);
}

byte[] euLicenseBytes = null;
try
{
    euLicenseBytes = Convert.FromBase64String(EULicenseBox.Text);
}
catch (FormatException)
{
    var dialog = new MessageDialog("Invalid license data. Please enter a valid Base64 string.");
    await dialog.ShowAsync();
    return;
}

// Now call the WCF service with the converted values
int i = await wcf.RegisterUserAsync(
    UserNameBox.Text,
    PasswordBox.Text,
    FirstNameBox.Text,
    LastNameBox.Text,
    dateOfBirth, // Pass DateTime instead of string
    euLicenseBytes, // Pass byte[] instead of string
    nonEuLicenseAccepted, // Pass bool instead of string
    EmailBox.Text,
    ContactNumberBox.Text
);

Double-check the parameter order in RegisterUserAsync to match your WCF service's actual expected types—I guessed based on your original code, so adjust if needed!

Additional Tips #

• Always add validation before conversion to catch bad input early and inform the user clearly.
• For sensitive fields like passwords, use a PasswordBox control instead of a regular TextBox (it hides input and is more secure).
• If your WCF service expects nullable types (e.g., DateTime?), you can use DateTime.TryParse and check if the parse succeeded before passing the value.

内容的提问来源于stack exchange，提问作者Armaan