Convert.IsDBNull causes exception in C#

[RICALJE]

Hi All,

Could you help me in my problem in working on a project that imports excel file to a datatable the validation is to catch all null values in the excel file because it will should not allow null values in the data table. Unfortunately my code dud not work. Please see my code below.

for (int i = 0; i < columnNameInt.Length -1; i++)
{
    try
    {
        myDataTable.Columns[columnNameIntExportEx[i]].DefaultValue = 0;
        myDataTable.Columns[columnNameIntExportEx[i]].AllowDBNull = false;
        myDataTable.Columns[columnNameIntExportEx[i]].ColumnName = columnNameInt[i];
    }
    catch
    {
        MessageBox.Show(columnNameIntExportEx[i]);
        for (int j = 0; j < myDataTable.Rows.Count; j++)
        {
            MessageBox.Show( "" + j);    
            if(Convert.IsDBNull(myDataTable.Rows[j][i]))
            {
                throw new Exception("Error found in row #[" + (j+1) + "]. Please check." );
            }
        }
    }
}
 

[Plater]

What part did not work on it?

EDIT: Do you know in your FOR loop you are skipping the last item?

[RICALJE]

Hi. I think i know now the problem. the problem is

it always by pass the if statement dont know why. its strange..
if(myDataTable.Rows[j][i].Equals(System.DBNull.Value))

for example in my excel file i have only 1 null value it will continue to load in my datatable in C#.

[Plater]

Well you should be checking for "" or empty string if its coming from excel.
Also, yuo should correct your FOR loop to include all the entries (you are never making it to the last entry with your current for loop logic)

[RICALJE]

thnx plater. i got the logic now. found out that the data table is correct but the datagrid have to contain a validation. we can close this issue now.:D