ASP.NET如何检查gridview中的每行？

Question

I want to add value into a Grid view via dropdownlist with a button. I want the ddTN.SelectedItem.value in the Grid view to be unique. No duplication How do I check every row for the ddTN.SelectedItem.value before adding a new ddTN.SelectedItem.value into the Grid view?

This are the codes that I have and it keep comparing the value with the first value in the gridview. Not the others.

I don't want to use a checkbox and such. All the example I found required using checkbox.

protected void Insert(object sender, EventArgs e)
{
   int i  = 0;
   var p  = 1;
   DataControlFieldCell cell = GridView1.Rows[i].Cells[p] as DataControlFieldCell;
   if (cell.Text != ddTN.SelectedItem.Value)
   {
      dt.Rows.Add(ddTN.SelectedValue, ddDuration.SelectedValue);
      ViewState["Customers"] = dt;
      this.BindGrid();
      label.Text = "";
      p++;
   }
   else
   {
      label.Text = "Exercise already inserted";
   }
}

Answer 1

It looks like you were intending on looping over the items in the grid but you have forgotten the looping mechanism. In your code, it always only checks the first item because i is initialized to 0 and never changes.

Try using a looping mechanism like a for loop or a while loop. Or, if you know the items in the grid from the beginning, perhaps use a hash table for quickly checking if the selected item already exists.

Keep trying, you are almost there!