在datagridview单元中动态插入数据

Question

我在数据gridview中动态添加了该列，并希望为其分配一些值。我正在使用以下代码...

        String qr = "SELECT Id, CONVERT(varchar, OrderItemId) AS Product, Quantity,CONVERT(varchar,CustomerId) AS Customer, ReturnRequestStatusId as'Return Request Status', CreatedOnUtc as Date FROM ReturnRequest";
        DataTable dtr = new DataTable();
        tp.populatedt(qr, dtr);
        dgvReturnRequests.DataSource = dtr;

        DataGridViewTextBoxColumn ord = new DataGridViewTextBoxColumn();
        ord.HeaderText = "Order #";
        ord.Name = "OrderCol";
        dgvReturnRequests.Columns.Insert(4, ord); // Here I added a new column

        foreach (DataGridViewRow dr in dgvReturnRequests.Rows)
        {
            string s = dr.Cells[1].Value.ToString();
            DataTable pn = new DataTable();
            tp.populatedt("Select p.pname,o.OrderId from Product p JOIN OrderItem o on p.Id=o.ProductId where o.Id='" + Convert.ToInt32(s) + "'", pn);
            foreach (DataRow dr1 in pn.Rows)
            {
                dr.Cells[1].Value = dr1["pname"].ToString();
                dr.Cells[4].Value = dr1["OrderId"].ToString(); // Here I am adding the value in a newly added column

            }
        }

显示了产品名称（pname），但是dr1 [“ OrderId”]。ToString（）的值未显示在该单元格中...检查下图中的输出。

我该如何解决？

Answer 1

您应确保dgvReturnRequests.Rows和pn.Rows不为空。否则，将无法达到循环且不会更新任何内容。

在方法的最后，您应该调用 dgvReturnRequests.Update（） ;；更新数据网格视图。

Answer 2

也许是因为您没有重新绑定gridview控件：

String qr = "SELECT Id, CONVERT(varchar, OrderItemId) AS Product, Quantity,CONVERT(varchar,CustomerId) AS Customer, ReturnRequestStatusId as'Return Request Status', CreatedOnUtc as Date FROM ReturnRequest";
DataTable dtr = new DataTable();
tp.populatedt(qr, dtr);
dgvReturnRequests.DataSource = dtr;

DataGridViewTextBoxColumn ord = new DataGridViewTextBoxColumn();
ord.HeaderText = "Order #";
ord.Name = "OrderCol";
dgvReturnRequests.Columns.Insert(4, ord);

foreach (DataGridViewRow dr in dgvReturnRequests.Rows)
{
    string s = dr.Cells[1].Value.ToString();
    DataTable pn = new DataTable();
    tp.populatedt("Select p.pname,o.OrderId from Product p JOIN OrderItem o on p.Id=o.ProductId where o.Id='" + Convert.ToInt32(s) + "'", pn);
    foreach (DataRow dr1 in pn.Rows)
    {
        dr.Cells[1].Value = dr1["pname"].ToString();
        dr.Cells[4].Value = dr1["OrderId"].ToString(); // Here I am adding the value in a newly added column
    }
    dtr.add(dr); // Function may differ in name. Maybe add a row.
}

dgvReturnRequests.DataSource=dtr;
dgvReturnRequests.DataBind();