asp.net - 如何在 asp.net 中动态获取 Html 控件 ID

Question

在这里，我需要在 asp.net Web 应用程序的动态网格中动态创建复选框，并且我使用以下代码来做理智，然后我需要使用 Find Control 检索这些 Id -((CheckBox)GrdShiftDetails.FindControl(Convert.ToString(vStrchkboxId))).Checked 但显示错误消息，如

空引用（对象引用未设置为对象的实例）

所以请帮我解决这个问题。

if (GrdShiftDetails.Rows[VintCurrentRow].Cells[coloumcount].Text != "00:00-00:00") {
            CheckBox chk = new CheckBox();
            chk.ID = "chk" + VintCurrentRow + coloumcount;
            chk.Checked = true;
            chk.Text = GrdShiftDetails.Rows[VintCurrentRow].Cells[coloumcount].Text;
            GrdShiftDetails.Rows[VintCurrentRow].Cells[coloumcount].Controls.Add(chk);
            // GrdShiftDetails.Rows[grdRow].Cells[coloumcount]
        }
        else {              
            CheckBox chk = new CheckBox();
            chk.ID = "chk" + VintCurrentRow + coloumcount;
            chk.Checked = false;
            chk.Text = GrdShiftDetails.Rows[VintCurrentRow].Cells[coloumcount].Text;
            GrdShiftDetails.Rows[VintCurrentRow].Cells[coloumcount].Controls.Add(chk);
        }
    }

Answer 1

添加一个

if(GrdShiftDetails.Rows.Count > 0 && GrdShiftDetails.Columns.Count > 0)
{

// your code
(GrdShiftDetails.Rows[VintCurrentRow].Cells[coloumcount].Text != "00:00-00:00") {
            CheckBox chk = new CheckBox();
            chk.ID = "chk" + VintCurrentRow + coloumcount;
            chk.Checked = true;
            chk.Text = GrdShiftDetails.Rows[VintCurrentRow].Cells[coloumcount].Text;
            GrdShiftDetails.Rows[VintCurrentRow].Cells[coloumcount].Controls.Add(chk);
            // GrdShiftDetails.Rows[grdRow].Cells[coloumcount]
        }
        else {              
            CheckBox chk = new CheckBox();
            chk.ID = "chk" + VintCurrentRow + coloumcount;
            chk.Checked = false;
            chk.Text = GrdShiftDetails.Rows[VintCurrentRow].Cells[coloumcount].Text;
            GrdShiftDetails.Rows[VintCurrentRow].Cells[coloumcount].Controls.Add(chk);
        }
    }
}

Answer 2

尝试这个：

foreach (GridViewRow objRow in GrdShiftDetails.Rows)
{
   TableCell cCheckCell = new TableCell();
   CheckBox chkCheckBox = new CheckBox();
   cCheckCell.Controls.Add(chkCheckBox);

   objRow.Cells.Add(cCheckCell);
}

Answer 3

如果您试图找到您添加的 CheckBox：试试这个：

//假设vStrchkboxId是CheckBox所需的ID

   for (int i = 0; i < GrdShiftDetails.Rows.Count; i++)
       if(((CheckBox)GrdShiftDetails.FindControl(Convert.ToString(vStrchkboxId))).Checked)
           //do something here.