Failed to load type Microsoft.Office.Interop.Excel._Application

I get an error when trying to debug code that reads Excel files. I am wondering if it is wrong to refer to "Microsoft.Office.Interop.Excel._Application", I get the following error.

doesn't mean version Microsoft.Office.Interop.Excelshould be 12? and not loading from my project build?

Could not load type 'Microsoft.Office.Interop.Excel._Application' from the assembly 'Dialog, Version = 1.0.0.0, Culture = neutral, PublicKeyToken = zero. The type is marked as suitable for the equivalence type, but the containing assembly does not load as fully trusted.

When I try to debug code, I get an exception before I can enter the function.

DataTable data = ExcelImport.GetDataFromFile(file);

My function

public static DataSet GetDataFromFile(string fileName)
    {
        Application oXL;
        Workbook oWB;
        Worksheet oSheet;
        Range oRng;

        // Needed to fix culture problem with excel files.
        CultureInfo cult = System.Threading.Thread.CurrentThread.CurrentCulture;
        System.Threading.Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");
        try
        {
            //  creat a Application object
            oXL = new Application();
            //   get   WorkBook  object
            oWB = oXL.Workbooks.Open(fileName, Missing.Value, Missing.Value,
                    Missing.Value, Missing.Value, Missing.Value,
                    Missing.Value, Missing.Value, Missing.Value,
                    Missing.Value, Missing.Value, Missing.Value, Missing.Value,
                    Missing.Value, Missing.Value);

            //   get   WorkSheet object
            oSheet = (Worksheet)oWB.Sheets[1];
            System.Data.DataTable dt = new System.Data.DataTable("dtExcel");
            DataSet ds = new DataSet();
            ds.Tables.Add(dt);

            //StringBuilder sb = new StringBuilder();
            int jValue = oSheet.UsedRange.Cells.Columns.Count;
            int iValue = oSheet.UsedRange.Cells.Rows.Count;
            //  get data columns
            for (int j = 1; j <= jValue; j++)
            {
                dt.Columns.Add("column" + j, Type.GetType("System.String"));
            }

            //  get data in cell
            for (int i = 1; i <= iValue; i++)
            {
                var test = (Range)oSheet.Cells[i, 1];

                if (!string.IsNullOrEmpty(test.Text))
                {
                    DataRow dr = ds.Tables["dtExcel"].NewRow();
                    for (int j = 1; j <= jValue; j++)
                    {
                        oRng = (Range)oSheet.Cells[i, j];
                        string strValue = oRng.Text.ToString();
                        dr["column" + j] = strValue;
                    }
                    ds.Tables["dtExcel"].Rows.Add(dr);
                }
            }
            oXL.Workbooks.Close();
            System.Threading.Thread.CurrentThread.CurrentCulture = cult;
            return ds;
        }
        catch (Exception ex)
        {
            throw new Exception("Error reading excel file", ex);
        }
    }