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I have this piece of code below which checks whether a checkbox for a certain row is clicked or not and depending on whether it is clicked or not shows either a true or false value.

foreach (DataGridViewRow r in testGV.Rows)
  DataGridViewCheckBoxCell cell = (DataGridViewCheckBoxCell)r.Cells["isSelected2"];
  if (Convert.ToBoolean(cell.Value)) // Checks if the value of the 
                                     // selected cell is true.
  // Currently returns null except when I press the checkbox and stop the test then
  // the checkbox turns to true because it is clicked.

The problem I am having is that sometimes the if statement returns a null value for no apparent reason. It only happens when I start the program and press the start test button which ultimately moves the row from one gridview to another. Then it will have a timer which collects data and is represented in the row but the moment I press stop test the if statement shows a true which is good but the moment I let the timer run for the test the value of the if statement turns to null which is bad. Here is where I initialize the columns for each gridview and also how I add a row to the gridviews.

public DataGridViewCheckBoxColumn chk1 = new DataGridViewCheckBoxColumn();
public DataGridViewCheckBoxColumn chk2 = new DataGridViewCheckBoxColumn();

Created as class variables.

This is where I load the form.
private void Form2_Load(object sender, EventArgs e)
    connectedGV.ColumnCount = 3;
    connectedGV.Columns[0].Name = "serial";
    connectedGV.Columns[0].ValueType = typeof(string);
    connectedGV.Columns[0].HeaderText = "Serial Number";
    connectedGV.Columns[1].Name = "mainboardfw";
    connectedGV.Columns[1].ValueType = typeof(string);
    connectedGV.Columns[1].HeaderText = "Firmware";
    connectedGV.Columns[2].Name = "opticalfirmware";
    connectedGV.Columns[2].ValueType = typeof(string);
    connectedGV.Columns[2].HeaderText = "Optical Firmware";
    chk1.HeaderText = "Selected";
    chk1.Name = "isSelected1";
    connectedGV.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill;

    testGV.ColumnCount = 5;
    testGV.Columns[0].Name = "serial";
    testGV.Columns[0].ValueType = typeof(string);
    testGV.Columns[0].HeaderText = "Serial Number";
    testGV.Columns[1].Name = "mainboardfw";
    testGV.Columns[1].ValueType = typeof(string);
    testGV.Columns[1].HeaderText = "Firmware";
    testGV.Columns[2].Name = "opticalfirmware";
    testGV.Columns[2].ValueType = typeof(string);
    testGV.Columns[2].HeaderText = "Optical Firmware";
    testGV.Columns[3].Name = "datacount";
    testGV.Columns[3].ValueType = typeof(string);
    testGV.Columns[3].HeaderText = "Data Count";
    testGV.Columns[4].Name = "startTime";
    testGV.Columns[4].ValueType = typeof(string);
    testGV.Columns[4].HeaderText = "StartTime";
    chk2.HeaderText = "Selected";
    chk2.Name = "isSelected2";
    testGV.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill;

Rows added here to connectedGV.
public void UnitConnected(object sender, APData ap)
    string[] row0 = { ap.DeviceSerial, ap.DeviceFirmware, ap.OpticalFirmware};
        countBox1.Text = connectedGV.Rows.Count.ToString();

       OutputBox.AppendText("Unit " + ap.DeviceSerial + " connected" + 

Finally row added to the second gridview where we are having issues.
public void OnBurnInStarted(APData ap)
        if (removeItemFromConnectedGrid(ap.DeviceSerial, connectedGV))
            string[] row0 = { ap.DeviceSerial, ap.DeviceFirmware, ap.OpticalFirmware, "0", DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"), };
            countBox1.Text = connectedGV.Rows.Count.ToString();
            countBox2.Text = UnitsUnderTestGridView.Rows.Count.ToString();


        OutputBox.AppendText("Starting Burn-in on " + ap.DeviceSerial +                 

I ultimately wanted to have a bool value correspond to the checkbox which would be ap.isSelected but I do not know how to get it to bind to a checkbox. I suspect its the way I am adding rows which is causing a null to appear but when I stop the test it clearly works.

If someone could help me figure out why the checkbox appears to be null when the timer runs out that would be great!

What I have tried:

I have tried moving things around, adding a variable to the checkbox and even adding a whole nother column but nothing seems to work. I have also tried sneaking into the row declarations, ap.isSelected but that doesn't seem to do anything.
Updated 4-Aug-22 9:39am

1 solution

You're adding column values except for your checkbox column:
string[] row0 = { ap.DeviceSerial, ap.DeviceFirmware, ap.OpticalFirmware, ???};

string[] row0 = { ap.DeviceSerial, ap.DeviceFirmware, ap.OpticalFirmware, "0", DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"), ??? };
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