指定的转换无效。指定的转换无效。怎么解决啊？

Question

 public DB_TH_GONGCHENGDataSet.carry_tableDataTable carryds;
        public DataRow[] drs;
        public void sumCarry()
        {
            float carrysumincoming=new float();
          //  float carrysumoutpay = new float();            carryds = new DB_TH_GONGCHENGDataSet.carry_tableDataTable();
            carry_tableTableAdapter.Fill(carryds);
            //drs = new DataRow();
           // carryds.Select("contr_Number='"+contr_Number+"'" );
            drs = carryds.Select("contr_Number='" + contr_Number + "'");
            foreach( DataRow da in drs)
            {
                carrysumincoming += ((float)(da["jzsr_Money"]));               //// carrysumoutpay += (float)da["jzzc_Money"];  //该剧提示：指定的转换无效。怎么解决啊？
            }
            textBox1.Text = carrysumincoming.ToString();
         //   textBox2.Text = carrysumoutpay.ToString();
           
        }

Answer 1

Console.WriteLine(da["jzsr_Money"].ToString());看看这里面是什么东西。

Answer 2

carrysumincoming += ((float)(da["jzsr_Money"])); carrysumincoming +=Convert.ToSingle(da["jzsr_Money"]);

Answer 3

jzsr_Money字段是float类型的数据吗？
可以试一试
Convert.ToSingle(da["jzsr_Money"].ToString());