错误检查列值是否为空或空

Question

I am trying to check if the column value ["CellNumber"] is emtpy or not with if condition. Even if the column cell value is not empty, it is prompting with message box instead of exit the foreach loop and updating the data.

    private void btnUpdate_Click(object sender, EventArgs e)
    {
        da = new SqlDataAdapter("select * from Measurement", con);
        SqlCommandBuilder cb = new SqlCommandBuilder(da);
        foreach (DataGridViewRow row in dgv.Rows)
        {
            if (Convert.ToString(row.Cells["CellNumber"].Value) == "")
            {
                MessageBox.Show("Please enter cellnumber", "Missing Information");
                return;
            }
        }
        try
        {
            da.Update(ds, "Measurement");
        }
        catch (DBConcurrencyException ex)
        {
            MessageBox.Show(ex.Message);
        }

Answer 1

Please check your number of rows in datagridview by doing

 DataGridView. If myDataGridView.Rows.Count == 0

If it is equal to 0 then it is empty

Answer 2

您使用字符串“ CellNumber”，难道不是int吗？

if (Convert.ToString(row.Cells["CellNumber"].Value) == "")

Answer 3

if (string.IsNullOrEmpty(row.Cells["CellNumber"].Value))
{ Your Code  }

Answer 4

Try this way

if (row.Cells["CellNumber"].Value == null || string.IsNullOrEmpty(row.Cells["CellNumber"].Value.ToString()))
{
   //rest
}

---

call dgv.CurrentRow.DataGridView.EndEdit(); to save changes in all cells before validating :)

private void btnUpdate_Click(object sender, EventArgs e)
{
    dgv.CurrentRow.DataGridView.EndEdit();
    dgv.EndEdit();
    ....

Answer 5

try to use the .EditedFormattedValue

        if (string.IsNullOrWhiteSpace(row.Cells["CellNumber"].EditedFormattedValue.ToString()))
        {
            MessageBox.Show("Please enter cellnumber", "Missing Information");
            return;
        }