如何将由新行和逗号分隔的字符串转换为C＃中的DataTable

Question

I have a string like this:

"Product,Price,Condition Cd,13,New Book,9,Used "

Which is being passed like this:

"Product,Price,Condition\\r\\Cd,13,New\\r\\nBook,9,Used"

How could I convert it to DataTable?

Trying to do it with this helper function:

            DataTable dataTable = new DataTable();
            bool columnsAdded = false;
            foreach (string row in data.Split(new string[] { "\r\n" }, StringSplitOptions.None))
            {
                DataRow dataRow = dataTable.NewRow();
                foreach (string cell in row.Split(','))
                {
                    string[] keyValue = cell.Split('~');
                    if (!columnsAdded)
                    {
                        DataColumn dataColumn = new DataColumn(keyValue[0]);
                        dataTable.Columns.Add(dataColumn);
                    }
                    dataRow[keyValue[0]] = keyValue[1];
                }
                columnsAdded = true;
                dataTable.Rows.Add(dataRow);
            }
            return dataTable;

However I don't get that "connecting cells with appropriate columns" part - my cells don't have ~ in string[] keyValue = cell.Split('~'); and I obviously get an IndexOutOfRange at DataColumn dataColumn = new DataColumn(keyValue[0]);

Answer 1

You can split given string into flattened string array in one call. Then you can iterate through the array and populate list of objects.

That part is optional, since you can immediately populate DataTable but I think it's way easier (more maintainable) to work with strongly-typed objects when dealing with DataTable .

string input = "Product,Price,Condition\r\nCd,13,New\r\nBook,9,Used";

string[] deconstructedInput = input.Split(new string[] { "\r\n", "," }, StringSplitOptions.None);

List<Product> products = new List<Product>();
for (int i = 3; i < deconstructedInput.Length; i += 3)
{
    products.Add(new Product
    {
        Name = deconstructedInput[i],
        Price = Decimal.Parse(deconstructedInput[i + 1]),
        Condition = deconstructedInput[i + 2]
    });
}

public class Product
{
    public string Name { get; set; }

    public decimal Price { get; set; }

    public string Condition { get; set; }
}

So, products collection holds 2 objects which you can easily iterate over and populate your DataTable .

Note: This requires further checks to avoid possible runtime exceptions, also it is not dynamic. That means, if you have differently structured input it won't work.

DataTable dataTable = new DataTable();

dataTable.Columns.Add(new DataColumn(nameof(Product.Name)));
dataTable.Columns.Add(new DataColumn(nameof(Product.Price)));
dataTable.Columns.Add(new DataColumn(nameof(Product.Condition)));

foreach (var product in products)
{
    var row = dataTable.NewRow();
    row[nameof(Product.Name)] = product.Name;
    row[nameof(Product.Price)] = product.Price;
    row[nameof(Product.Condition)] = product.Condition;
    dataTable.Rows.Add(row);
}

Answer 2

You can do that simply with Linq (and actually there is LinqToCSV on Nuget, maybe you would prefer that):

void Main()
{
    string data = @"Product,Price,Condition
Cd,13,New
Book,9,Used
";
    var table = ToTable(data);
    Form f = new Form();
    var dgv = new DataGridView { Dock = DockStyle.Fill, DataSource = table };
    f.Controls.Add(dgv);
    f.Show();
}

private DataTable ToTable(string CSV)
{
    DataTable dataTable = new DataTable();
    var lines = CSV.Split(new char[] { '\n' }, StringSplitOptions.RemoveEmptyEntries);
    foreach (var colname in lines[0].Split(','))
    {
        dataTable.Columns.Add(new DataColumn(colname));
    }
    foreach (var row in lines.Where((r, i) => i > 0))
    {
        dataTable.Rows.Add(row.Split(','));
    }
    return dataTable;
}

Answer 3

Based on your implementation, I have written the code for you, I have not tested it. But you can use the concept.

DataRow dataRow = dataTable.NewRow();
int i = 0;
foreach (string cell in row.Split(','))
{
    if (!columnsAdded)
    {
        DataColumn dataColumn = new DataColumn(cell);
        dataTable.Columns.Add(dataColumn);
    }
    else
    {
        dataRow[i] = cell;
    }
    i++;
}
if(columnsAdded)
{
    dataTable.Rows.Add(dataRow);
}
columnsAdded = true;