Access VBA From In C# Code

[sanndeb]

I have an excel file with a customized command button, named "Credit Matrix", the click of the button shows a VBA from like the picture below. What i need is to populate the textfields and comboboxes of the VBA from and click on the "ok" button. I tried the following to access the VBA from, but i failed..... :(

            Excel.Application xlApp;
            Excel.Workbook xlBook;
            Excel.Worksheet xlSheet1, xlSheet2, xlSheet3;
            xlApp = new Excel.Application();
            xlApp.Visible = true;
            xlBook =
                xlApp.Workbooks.Open(
                    @"excelPath", 3,
                    false, 5, "", "", true, Excel.XlPlatform.xlWindows, "\t", true, false, 0, true, Missing.Value, false);
            CommandBar oCommandBar = xlApp.CommandBars["Worksheet Menu Bar"];
            StringBuilder sb = new StringBuilder();
            try
            {
                for (var i = 1; i < xlApp.CommandBars.Count; i++)
                {
                    var o = oCommandBar.Controls[i];
                    if (o.Caption.IndexOf("Credit Matrix") >= 0)
                    {
                        CommandBarButton b = o.get_accChild("1") as CommandBarButton;
                        b.Execute();
                        break;
                    }
                }
            }
            catch
            {
                xlApp.Quit();
            }
            UserForm form;
            Microsoft.Vbe.Interop.Forms.Control c;
            foreach (VBComponent mod in xlBook.VBProject.VBComponents)
            {
                sb.AppendLine(mod.Type.ToString());
                if (mod.Type.ToString() != "vbext_ct_MSForm") continue;
                form = (UserForm)mod.Designer; //gives null
                for (int i = 1; i < form.Controls.Count; i++)
                {
                    c = (Microsoft.Vbe.Interop.Forms.Control)form.Controls.Item(i); // to fetch the controls of the form
                }
            }

Pls help to get the from control and its child controls... Thanks