i am getting below error

Error converting data type nvarchar to date in

cmd.Parameters.AddWithValue("@Inv_Date", inv_Date);

private void InsertRows(string barcode, string qty, string weight, 
    string cat_id, string contno, string c_agent_id, string loc_id, 
    string sup_id, decimal rate, decimal freight, string forwarder, 
    decimal trucking_rate, decimal clearing_rate, decimal Weight_Zone, 
    string inv_no, string inv_date)
{
    //con.Open();
    SqlCommand cmd = new SqlCommand("Sp_Insert_ContnoM", con);

    cmd.CommandType = CommandType.StoredProcedure;
    cmd.Parameters.AddWithValue("@Action", "Insert");
    cmd.Parameters.AddWithValue("@ContNo", barcode);
    cmd.Parameters.AddWithValue("@ConWeight", weight);
    cmd.Parameters.AddWithValue("@No_Of_Bales", qty);
    cmd.Parameters.AddWithValue("@Contrackno", contno);
    cmd.Parameters.AddWithValue("@Cat_Id", cat_id);
    cmd.Parameters.AddWithValue("@Clearning_agent_ID", c_agent_id);
    cmd.Parameters.AddWithValue("@Loc_ID", loc_id);
    cmd.Parameters.AddWithValue("@Supplier_ID", sup_id);
    cmd.Parameters.AddWithValue("@Container_Rate", rate);
    cmd.Parameters.AddWithValue("@Freight_Charges", freight);
    cmd.Parameters.AddWithValue("@Forwarder_ID", forwarder);
    cmd.Parameters.AddWithValue("@Trucking_Charges", trucking_rate);
    cmd.Parameters.AddWithValue("@Clearning_Agent_Charges", clearing_rate);
    cmd.Parameters.AddWithValue("@Weight_Zone", Weight_Zone);
    cmd.Parameters.AddWithValue("@Inv_No", inv_no);
    cmd.Parameters.AddWithValue("@Inv_Date", inv_Date);
    cmd.Parameters.AddWithValue("@entrydate", DateTime.Now);
    con.Open();
    cmd.ExecuteNonQuery();
    int i = cmd.ExecuteNonQuery();
    if (i > 0)
    {
        Response.Write("<script>alert('Record save successuly')</script>");
    }
    else
    {
        Response.Write("<script>alert('Record Not save')</script>");
    }
    con.Close();
}