My code is always entering the exception, does not matter if I try to "treat" the cell with NULL using IF/ELSE clauses.
My catch System.Exception error is: "Object reference not set to an instance of an object"
Situation: If I enter a NULL value on the Datagrid, an error will occur and the rest of the data is not saved.
private void ExportToExcel()
{
// Creating a Excel object.
Microsoft.Office.Interop.Excel._Application excel = new Microsoft.Office.Interop.Excel.Application();
Microsoft.Office.Interop.Excel._Workbook workbook = excel.Workbooks.Add(Type.Missing);
Microsoft.Office.Interop.Excel._Worksheet worksheet = null;
try
{
worksheet = workbook.ActiveSheet;
worksheet.Name = "ExportedFromDatGrid";
int cellRowIndex = 1;
int cellColumnIndex = 1;
//Loop through each row and read value from each column.
for (int i = -1; i < dataGridView1.Rows.Count - 1; i++)
{
for (int j = 0; j < dataGridView1.Columns.Count; j++)
{
// Excel index starts from 1,1. As first Row would have the Column headers, adding a condition check.
if (cellRowIndex == 1)
{
worksheet.Cells[cellRowIndex, cellColumnIndex] = dataGridView1.Columns[j].HeaderText;
}
else
{
if (dataGridView1.Rows[i].Cells[j].Value.ToString() != null)
{
worksheet.Cells[cellRowIndex, cellColumnIndex] = dataGridView1.Rows[i].Cells[j].Value.ToString();
}
else
{
worksheet.Cells[cellRowIndex, cellColumnIndex] = String.Empty;
}
// working:
//worksheet.Cells[cellRowIndex, cellColumnIndex] = dataGridView1.Rows[i].Cells[j].Value.ToString();
}
cellColumnIndex++;
}
cellColumnIndex = 1;
cellRowIndex++;
}
//Getting the location and file name of the excel to save from user.
SaveFileDialog saveDialog = new SaveFileDialog();
saveDialog.Filter = "Excel files (*.xlsx)|*.xlsx|All files (*.*)|*.*";
saveDialog.FilterIndex = 2;
if (saveDialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{
workbook.SaveAs(saveDialog.FileName);
MessageBox.Show("Export Successful");
}
}
catch (System.Exception ex)
{
MessageBox.Show(ex.Message);
}
finally
{
excel.Quit();
workbook = null;
excel = null;
}
} // end ExportToExcel
