Question

I have a class from which I want to get values from combo box and textboxes, but when I pass the value it shows the following error:

An object reference is required for the non-static field, method, or property 

Here is the code

public class Device1
{
        public int dwMachineNumber = cboMachineNo.SelectedIndex;
        public int dwBaudrate = 9600;
        public int dwCommPort = CboComPort.SelectedIndex;
        public string dwIPAddress = tbIPAdd.Text.Trim();
        public int dwPort = int.Parse(tbPort.Text.Trim());
        public int dwPassWord = int.Parse(tbPwd.Text.Trim());
}

private bool OpenDevice(int flag)
{
    bool result = false;   
    int DEVICE_BUSY = 0;
    Device1 dww = new Device1();
    try{
       result = OpenCommPort(dww.dwMachineNumber,
                       dww.dwBaudrate, 
                       dww.dwCommPort, 
                       dww.dwIPAddress, 
                       dww.dwPassWord,
                       dww.dwPort,
                       flag);

}

Answer 1

Here, I think this is what you’re trying to do..

You maybe want to create your Device1 class to look like this:

public class Device1
{
    public int dwMachineNumber;
    public int dwBaudrate;
    public int dwCommPort;
    public string dwIPAddress;
    public int dwPort;
    public int dwPassWord;

    public Device1(int dwMachineNumber, int dwBaudrate, int dwCommPort, string dwIPAddress, int dwPort, int dwPassWord)
    {
        this.dwMachineNumber = dwMachineNumber;
        this.dwBaudrate = dwBaudrate;
        this.dwCommPort = dwCommPort;
        this.dwIPAddress = dwIPAddress;
        this.dwPort = dwPort;
        this.dwPassWord = dwPassWord;
    }
}

Then in the code-behind of your Winforms form you need to add something similar to this:

    private void btnMyButton_Click(object sender, EventArgs e)
    {
        Device1 myDevice1 = new Device1(cboMachineNo.SelectedIndex, 9600, cboComPort.SelectedIndex, tbIPAdd.Text.Trim(), int.Parse(tbPort.Text.Trim(), int.Parse(tbPwd.Text.Trim());

        // Now do something with your populated Device1 object.
    }

For this example, I added the code to the event handler of a button. You need to add it where you want it to happen.

This code will take the values from the winform and pass them to the class. I believe this is what you want to do.