输入字符串格式不正确，来看看吧，亲！！！！
报错，出现“输入字符串格式不正确”，数据类型格式都对着呢，和数据库也对应！问题是sqlParams[1].Value = int.Parse(this.ViewState["PopedomId"].ToString());取不到值。
代码如下：

 private bool GetMaintainInfo(out string AlertError)

    {

        bool flag = false;

        AlertError = "";

        new SysClass();

        try

        {

            string sQL = " select VehicleType,VehicleTypeID,MaintainCycle,CycleUnit,PopedomId from VehicleType where VehicleType = @VehicleType and PopedomId=@PopedomId";

            SqlParameter[] sqlParams = new SqlParameter[] { 

                new SqlParameter("@VehicleType", SqlDbType.VarChar, 50), 

                new SqlParameter("@PopedomId", SqlDbType.Int) 

            };

            sqlParams[0].Value = this.TextBox4.Text.Trim().ToString();//车辆类型

            //string test0 = this.TextBox4.Text.Trim().ToString();

            sqlParams[1].Value = int.Parse(this.ViewState["PopedomId"].ToString());//错误所在！！！！！！！！！这里的值为空，取不到值。

            //int test = int.Parse(this.ViewState["PopedomId"].ToString());

            DBClass class2 = new DBClass("ConnStr");

            class2.ReadData(sQL, sqlParams);

            while (class2.MyReader.Read())

            {

                this.ViewState["MaintainCycle"] = class2.MyReader["MaintainCycle"];

                this.ViewState["CycleUnit"] = class2.MyReader["CycleUnit"];

                flag = true;

            }

            class2.MyReader.Close();

            class2.MyReader.Dispose();

            class2.Conn.Close();

            class2.Conn.Dispose();

            if (!flag)

            {

                AlertError = "车辆类型【" + this.TextBox4.Text.Trim() + "】未配置";

  &