Input string was not in a correct format

Question

I have a small problem here. When I tried to do the following steps,

string set1="123.10,134.40";
string set2="17,134"; 
List<string> List1 = new List<string>(set1.Split(','));
List<string> List2 = new List<string>(set2.Split(','));

var QueryResult = from D1 in List1 
                  from E1 in List2
                  select new
                  {
                      D1,
                      E1
                  };
DataTable tempDT = new DataTable();
tempDT.Columns.Add("Data1", typeof(int));
tempDT.Columns.Add("Data2", typeof(string));

foreach (var item in QueryResult)
{
    tempDT.Rows.Add(new object[] {Convert.ToInt32(item.E1.ToString()),
    Convert.ToString(item.D1.ToString()) });
}

When I try to add those values to the tempDT I am getting an exception:

Input string was not in a correct format.

How do I fix this issue?

Answer 1

It is because you are using Convert.ToInt32 on a string that contains a decimal character.

Answer 2

The code you posted worked just fine, so it means the problem is with your real data.

Most likely, you have something like this:

string set2="17,134,,20"; 

Meaning empty item which will crash the code.

Remove such empty items with:

List<string> List2 = new List<string>(set2.Split(new char[] {','}, StringSplitOptions.RemoveEmptyEntries));

To be totally safe from that error, use TryParse instead:

int e1;
foreach (var item in QueryResult)
{
    if (Int32.TryParse(item.E1, out e1))
    {
        tempDT.Rows.Add(new object[] { e1, item.D1 });
    }
}

This will just ignore any invalid values, not adding them to the data table.