GridView绑定记录为空显示表头

 protected void btnQuery_Click(object sender, EventArgs e)
    {
        string queryCondition = "1=1";
        string name = this.tbName.Text.Trim();
        string idCode = this.tbIDCode.Text.Trim();
        string flowInDate = this.tbFlowInDate.Text.Trim();
        string mateName = this.tbMateName.Text.Trim();
        string mateIdCode = this.tbMateIDCode.Text.Trim();
        string reportDate = this.tbReportDate.Text.Trim();
        string verifyState = this.ddlVerifyState.SelectedItem.Text;
        if (!name.Equals(""))
        {
            queryCondition = queryCondition + " and Name='" + name + "'";
        }
        if (!idCode.Equals(""))
        {
            queryCondition = queryCondition + " and ID_Code='" + idCode + "'";
        }
        if (!flowInDate.Equals(""))
        {
            queryCondition = queryCondition + " and FlowIn_Date='" + Convert.ToDateTime(flowInDate) + "'";
        }
        if (!mateName.Equals(""))
        {
            queryCondition = queryCondition + " and Mate_Name='" + mateName + "'";
        }
        if (!mateIdCode.Equals(""))
        {
            queryCondition = queryCondition + " and Mate_IDCode='" + mateIdCode + "'";
        }
        if (!reportDate.Equals(""))
        {
            queryCondition = queryCondition + " and Report_Date='" + Convert.ToDateTime(reportDate) + "'";
        }
        if (!verifyState.Equals("--请选择--"))
        {
            queryCondition = queryCondition + " and Verify_Stat='" + verifyState + "'";
        }
        //this.gvFlowing.DataSource = bibRecDataBll.GetByWhere(queryCondition);
        //this.gvFlowing.DataBind();
        DataSet ds = bibRecDataBll.GetByWhere(queryCondition);
        if (ds.Tables[0].Rows.Count == 0)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("FlowIn_ID");
            dt.Columns.Add("FI_H_ID");
            dt.Columns.Add("Name");
            dt.Columns.Add("ID_Code");
            dt.Columns.Add("FlowIn_Date");
            dt.Columns.Add("MarryStat");
            dt.Columns.Add("Mate_Name");
            dt.Columns.Add("Verify_Stat");
            dt.Rows.Add(dt.NewRow());
            this.gvFlowing.DataSource = dt;
            this.gvFlowing.DataBind();
            int columnCount = dt.Columns.Count;
            this.gvFlowing.Rows[0].Cells.Clear();
            this.gvFlowing.Rows[0].Cells.Add(new TableCell());
            this.gvFlowing.Rows[0].Cells[0].ColumnSpan = columnCount;
            this.gvFlowing.Rows[0].Cells[0].Text = "没有记录";
            this.gvFlowing.Rows[0].Cells[0].Style.Add("text-align", "center");

        }
        else
        {
            this.gvFlowing.DataSource = bibRecDataBll.GetByWhere(queryCondition);
            this.gvFlowing.DataBind();
        }
       
    }