how to validate all datagridview cells?

Question

I have a DataGridView that consist of some rows and columns. I want to check all cells of my DataGridView for empty cells, if any cell is empty in any row then give me a message. I have a code for doing that but it checks only the cells of the first row This is my code:

    foreach (DataGridViewRow rw in dgv_absence.Rows)
    {
        if (rw.Cells[0].Value == null || rw.Cells[0].Value == DBNull.Value || string.IsNullOrWhiteSpace(rw.Cells[0].FormattedValue.ToString()) || rw.Cells[1].Value == null || rw.Cells[1].Value == DBNull.Value || string.IsNullOrWhiteSpace(rw.Cells[1].FormattedValue.ToString()))
        {
            MessageBox.Show("message","title");
            return;
        }
        else
        {
            for (int i = 0; i < dgv_absence.Rows.Count - 1; i++)
            {
                // do some thing
            }
        }
    }

Answer 1

Instead of Cells[0], which only targets the first cell of each row, you need to also loop through the cells in an inner for loop. Like this:

        foreach (DataGridViewRow row in dataGridView.Rows)
        {
            foreach (DataGridViewCell cell in row.Cells)
            {

            }
        }

Answer 2

This is what I would do.

The DataGrid control on Windows Form can read errors from objects implementing IDataErrorInfo

As MSDN says.

IDataErrorInfo Provides the functionality to offer custom error information that a user interface can bind to.

Your POCO object inside the data source collection for the grid, should implement IDataErrorInfo let's say something like this:

public class MyEntity : IDataErrorInfo
{
    public string this[string columnName]
    {
        get
        {
            // here you can validate each property of your class (POCO object)
            var result = string.Join(Environment.NewLine, Validator.Validate(this, columnName).Select(x => x.ErrorMessage));
            return result;
        }
    }

    public string Error
    {
        get
        {
            // here you can errors related to the whole object (ex: Password, and PasswordConfirmation do not match)
            return string.Join(Environment.NewLine, Validator.Validate(this)
                                                                .Select(x => x.ErrorMessage));
        }
    }

    public Boolean IsValid
    {
        get { return string.IsNullOrEmpty(Error); }
    }
}

Then you could use some validation technique to set up your validation rules.

I like to use DataAnnotation to implement my validation logic.

So, let's say your class has a property (name) that cannot be null you class could be:

public class MyEntity : IDataErrorInfo
{
    [Required]
    public string Name { get; set; }

    public string this[string columnName]
    {
        get
        {
            // here you can validate each property of your class (POCO object)
            var result = string.Join(Environment.NewLine, Validator.Validate(this, columnName).Select(x => x.ErrorMessage));
            return result;
        }
    }

    public string Error
    {
        get
        {
            // here you can validate errors related to the whole object (ex: Password, and PasswordConfirmation do not match)
            return string.Join(Environment.NewLine, Validator.Validate(this)
                                                                .Select(x => x.ErrorMessage)
                                                                .Union(ModelError.Select(m => m.Value)));
        }
    }

    public Boolean IsValid
    {
        get { return string.IsNullOrEmpty(Error); }
    }
}

Then if you use a validator like this

public class Validator : IValidator
{
    public IEnumerable<ErrorInfo> Validate(object instance)
    {
        IEnumerable<ErrorInfo> errores = from property in instance.GetType().GetProperties()
            from error in GetValidationErrors(instance, property)
            select error;
        if (!errores.Any())
        {
            errores = from val in instance.GetAttributes<ValidationAttribute>(true)
                where
                    val.GetValidationResult(null, new ValidationContext(instance, null, null)) !=
                    ValidationResult.Success
                select
                    new ErrorInfo(null,
                        val.GetValidationResult(null, new ValidationContext(instance, null, null)).ErrorMessage,
                        instance);
        }

        return errores;
    }

    public IEnumerable<ErrorInfo> Validate(object instance, string propertyName)
    {
        PropertyInfo property = instance.GetType().GetProperty(propertyName);
        return GetValidationErrors(instance, property);
    }

    private IEnumerable<ErrorInfo> GetValidationErrors(object instance, PropertyInfo property)
    {
        var context = new ValidationContext(instance, null, null);
        context.MemberName = property.Name;
        IEnumerable<ErrorInfo> validators = from attribute in property.GetAttributes<ValidationAttribute>(true)
            where
                attribute.GetValidationResult(property.GetValue(instance, null), context) !=
                ValidationResult.Success
            select new ErrorInfo(
                property.Name,
                attribute.FormatErrorMessage(property.Name),
                instance
                );

        return validators.OfType<ErrorInfo>();
    }
}

The errors will appear on the grid per cell or per row depending on the error.

Notice that you should also implement INotifyPropertyChanged if you are planning to in-line editing your objects.

This approach has the benefit of decoupling the validation logic from the user interface.

Answer 3

you can call this method it return if one cell is empty or not:

 public Boolean IsDataGridViewEmpty( DataGridView dataGridView)
    {
        bool isEmpty = false;
        foreach (DataGridViewRow row in dataGridView.Rows)
        {
            if (!row.IsNewRow)
            {
                foreach (DataGridViewCell cell in row.Cells)
                {
                    //if (!string.IsNullOrEmpty(cell.Value.ToString ()))
                    //{
                    if (string.IsNullOrEmpty(cell.Value.ToString().Trim()))
                    {
                        isEmpty = true;
                        break; // TODO: might not be correct. Was : Exit For
                        //  }
                    }
                }
            }
        }
        return isEmpty;
    }

you can call it by:

  if (!IsDataGridViewEmpty( dgv_absence))
        {
           MessageBox.Show("message","title");
             return;
        }