System.InvalidCastException：将数据发布到sql表时，指定的强制转换无效

Question

I am creating an IT inventory system and need to add all the workstation information to the Workstation table. i've switched on the debugger and going through the code I receive the error

"System.InvalidCastException: 'Specified cast is not valid.'

The error comes from the line code of if ((bool)item["Wkst_Status"])

I have not tried anything as yet as i am new to C#, asp.net as a beginner.

foreach (DataRow item in dt.Rows)
{
    int n = dataGridView1.Rows.Add();
    dataGridView1.Rows[n].Cells[0].Value = item["Emp_Name"].ToString();
    dataGridView1.Rows[n].Cells[1].Value = item["Emp_Surname"].ToString();
    dataGridView1.Rows[n].Cells[2].Value = item["Department"].ToString();
    dataGridView1.Rows[n].Cells[3].Value = item["Company"].ToString();
    dataGridView1.Rows[n].Cells[4].Value = item["Hostname"].ToString();

    if ((bool)item["Wkst_Status"])
    {
        dataGridView1.Rows[n].Cells[5].Value = "Active";
    }
    else
    {
        dataGridView1.Rows[n].Cells[5].Value = "Inactive";
    }

    dataGridView1.Rows[n].Cells[6].Value = item["Make"].ToString();
    dataGridView1.Rows[n].Cells[7].Value = item["Model"].ToString();
    dataGridView1.Rows[n].Cells[8].Value = item["SerialNumber"].ToString();
    dataGridView1.Rows[n].Cells[9].Value = tem["ProductNumber"].ToString();
    dataGridView1.Rows[n].Cells[10].Value = item["Purch_Date"].ToString();
    dataGridView1.Rows[n].Cells[11].Value = item["WExpiry_Date"].ToString();
    dataGridView1.Rows[n].Cells[12].Value = item["Memory"].ToString();
    dataGridView1.Rows[n].Cells[13].Value = item["Processor"].ToString();
    dataGridView1.Rows[n].Cells[14].Value = item["HDD"].ToString();
    dataGridView1.Rows[n].Cells[15].Value = item["OS"].ToString();
}

after entering the data in the app the data should be written to the sql table

Answer 1

As a start you can do it in a safer way:

Instead of this:

if ((bool)item["Wkst_Status"])

Use this:

var isActive = Convert.ToBoolean(item["Wkst_Status"]);

if (isActive  == true)
    {
        dataGridView1.Rows[n].Cells[5].Value = "Active";
    }
    else
    {
        dataGridView1.Rows[n].Cells[5].Value = "Inactive";
    }

You can also do null checks, but in your case that won't matter, because probably if the item["Wkst_Status"] is null, you would want the value of the cell to say "InActive"

Answer 2

ty this:

if(item["Wkst_Status"] != null)
{
    dataGridView1.Rows[n].Cells[5].Value = (Convert.ToBoolean(item["Wkst_Status"]) ?"Active":"Inactive");
}