参数化查询 需要参数 但未提供该参数

Question

使用参数化查询 sql parameter
insert 时，我的一个DateTime类型的字段想传入一个null值，但会报错“参数化查询 需要参数 但未提供该参数”
高手帮忙～～

Answer 1

数据库字段是不是not null，还有要是传入null的话  建议还是在数据库里面设置默认值是null，不然很容易出错····

Answer 2

 public int SaveData(TaskManageInfo taskManage)
        {
            int index = 0;
            string strSQL = null;            if (taskManage.ID == 0)
            {
                strSQL = "INSERT INTO TaskManage(ID,Name,Project,Block,Type,Description,Res,PersonInCharge,RegisterPerson,State,PlanToFinish,IsMailRemind,IsPublic,IsUndetermined,FinishTime,FinishReport) ";
                strSQL += "VALUES(@ID,@Name,@Project,@Block,@Type,@Description,@Res,@PersonInCharge,@RegisterPerson,@State,@PlanToFinish,@IsMailRemind,@IsPublic,@IsUndetermined,@FinishTime,@FinishReport)";
                taskManage.ID = DBHelper.GetMaxID("TaskManage");
            }
            else
            {
                strSQL = "UPDATE Student SET ID = @ID,Name = @Name,Project = @Project,Block = @Block,Type = @Type,Description = @Description,Res = @Res,PersonInCharge = @PersonInCharge,RegisterPerson = @RegisterPerson,State = @State,PlanToFinish = @PlanToFinish,IsMailRemind = @IsMailRemind,IsPublic = @IsPublic,IsUndetermined = @IsUndetermined,FinishTime = @FinishTime,FinishReport = @FinishReport WHERE ID=@ID;";
            }            SqlParameter[] sqlParameter = GetParameters();
            sqlParameter[index++].Value = taskManage.ID;
            sqlParameter[index++].Value = taskManage.Name;
            sqlParameter[index++].Value = taskManage.Project;
            sqlParameter[index++].Value = taskManage.Block;
            sqlParameter[index++].Value = taskManage.Type;
            sqlParameter[index++].Value = taskManage.Description;
            sqlParameter[index++].Value = taskManage.Res;
            sqlParameter[index++].Value = taskManage.PersonInCharge;
            sqlParameter[index++].Value = taskManage.RegisterPerson;
            sqlParameter[index++].Value = taskManage.State;
            sqlParameter[index++].Value = taskManage.PlanToFinish;
            sqlParameter[index++].Value = taskManage.IsMailRemind;
            sqlParameter[index++].Value = taskManage.IsPublic;
            sqlParameter[index++].Value = taskManage.IsUndetermined;
            sqlParameter[index++].Value = taskManage.FinishTime;
            sqlParameter[index++].Value = taskManage.FinishReport;            try
            {
                DBHelper.ExecuteNonQuery(strSQL, sqlParameter);
            }
            catch(Exception ex)
            {
                throw (ex);
            }
            return taskManage.ID.Value;        }//-----------------------------------------------------------------------------------
        /// <summary>
        /// 初始化参数
        /// </summary>
        /// <returns></returns>
        private SqlParameter[] GetParameters()
        {
            SqlParameter[] parms;            parms = new SqlParameter[] {
                  new SqlParameter("@ID",SqlDbType.Int),
                  new SqlParameter("@Name",SqlDbType.NVarChar,50),
                  new SqlParameter("@Project",SqlDbType.NVarChar,50),
                  new SqlParameter("@Block",SqlDbType.NVarChar,50),
                  new SqlParameter("@Type",SqlDbType.NVarChar,50),
                  new SqlParameter("@Description",SqlDbType.NVarChar,500),
                  new SqlParameter("@Res",SqlDbType.NVarChar,500),
                  new SqlParameter("@PersonInCharge",SqlDbType.NVarChar,50),
                  new SqlParameter("@RegisterPerson",SqlDbType.NVarChar,50),
                  new SqlParameter("@State",SqlDbType.Int),
                  new SqlParameter("@PlanToFinish",SqlDbType.DateTime,8,""),
                  new SqlParameter("@IsMailRemind",SqlDbType.Int),
                  new SqlParameter("@IsPublic",SqlDbType.Int),
                  new SqlParameter("@IsUndetermined",SqlDbType.Int),
                  new SqlParameter("@FinishTime",SqlDbType.DateTime),
                  new SqlParameter("@FinishReport",SqlDbType.NVarChar,500),
          };
            return parms;
        }//-------------------------------------------------------------------------------
 protected void btnSave_Click(object sender, EventArgs e)
    {
        TaskManageBO taskManageBO = new TaskManageBO();
        try
        {
            int isSuccess = taskManageBO.Save(SetInfo());
            if (isSuccess == 1)
            {
                Page.ClientScript.RegisterStartupScript(this.GetType(), "OK", "<script>alert('保存成功！')</script>");
            }
        }
        catch(Exception ex)
        {
            string str = ex.Message.Replace("'", "\\'");
            Page.ClientScript.RegisterStartupScript(this.GetType(), "OK", "<script>alert('" + str + "');</script>");
        }
    }
    
    //---------------封装实体------------------
    private TaskManageInfo SetInfo()
    {
        DateTime? nullDateTime = null;
        TaskManageInfo info = new TaskManageInfo();
        info.ID = int.Parse(hidID.Value);
        info.Name = this.txtName.Text;//任务名称
        info.Project = this.txtProject.Text;//所属项目
        info.Block = this.txtBlock.Text;//所属模块
        info.Type = this.txtType.Text;//任务类型
        info.Description = this.txtDescription.Text;//任务描述
        info.PlanToFinish = txtPlanToFinish.Text == "" ? nullDateTime : DateTime.Parse(txtPlanToFinish.Text); //计划完成时间
        info.PersonInCharge = txtPersonInCharge.Text; //责任人
        info.Res = txtRes.Text; //备注
        info.IsMailRemind = this.chbMail.Checked == true ? 1 : 0; //是否邮件提醒
        info.IsPublic = this.chbIsPublic.Checked == true ? 1 : 0; //是否公开任务
        info.IsUndetermined = null;//计划完成时间（是否待写） 暂时不用此功能
        info.State = 0;//任务状态，默认为“处理中”
        info.RegisterPerson = this.userName; //登记人
        info.FinishReport = "";//结束报告，任务结束时赋值，这里先赋空值
        info.FinishTime = null;//结束时间
        return info;
    }

Answer 3

贴出代码看看
parameters[1].Value = model.A?? DBNull.Value;

Answer 4

数据库字段是不是not null，还有要是传入null的话 建议还是在数据库里面设置默认值是null，不然很容易出错····

Answer 5

我定义了可空的DateTime类型，也出现了类似的问题。parameters[1].Value = model.A?? DBNull.Value;但是这个不行。怎么解决？