列表查询组件代码, 简化拼接条件SQL语句的麻烦

控件代码及测试例子：https://files.cnblogs.com/wuhuacong/CommonSearch.rar 

使用场景: 在列表页面中,一般有好几个条件, 用户进行查询时候,需要根据这几个条件进行过滤查询.但在组装这些过滤条件的时候，代码比较烦琐臃肿，本组件代码为解决该问题而设计。

使用目的:  1.减少对参数非空的条件判断 2. 可以构造出参数化的DbCommand对象,简化操作. 3.适当修改后可以用于其他数据访问的参数化参数生成.4.构造Sql语句或者参数化条件更加易读

1. 生成SQL条件语句
如有几个字段，需要根据不同的字段进行过滤，想生成的SQL语句如下：
 Where (1=1)  AND AA2  Like  '%AA2Value%' AND AA6  >=  'Value6' AND AA7  <=  'value7' AND AA3  =  'Value3' AND AA4  <  'Value4' AND AA5  >  'Value5' AND AA  <>  '1'
 
那么代码如下：

            SearchCondition search = new SearchCondition();
            search.AddCondition("AA", 1, SqlOperator.NotEqual)
                .AddCondition("AA2", "AA2Value", SqlOperator.Like)
                .AddCondition("AA3", "Value3", SqlOperator.Equal)
                .AddCondition("AA4", "Value4", SqlOperator.LessThan)
                .AddCondition("AA5", "Value5", SqlOperator.MoreThan)
                .AddCondition("AA6", "Value6", SqlOperator.MoreThanOrEqual)
                .AddCondition("AA7", "value7", SqlOperator.LessThanOrEqual);
            string conditionSql = search.BuildConditionSql();

2. 生成基于Enterprise Library的DbCommand对象

            Database db = DatabaseFactory.CreateDatabase();
            SearchCondition search = new SearchCondition();
            search.AddCondition("Name", "测试" , SqlOperator.Like)
                  .AddCondition("ID", 1, SqlOperator.MoreThanOrEqual);
            DbCommand dbComand  = search.BuildDbCommand(db, "select Comments from Test", " Order by Name");
            using (IDataReader dr = db.ExecuteReader(dbComand))
            {
                while (dr.Read())
                {
                    this.txtSql.Text += "\r\n" + dr["Comments"].ToString();
                }
            }

下面是该控件的类对象图解


下面我们比较一下使用该控件和不使用在列表查询页面中的代码，可以看出使用了控件后的代码大大较少了，并且可读性也增强了

1. 使用该控件, 列表查询页面中的代码

    private string GetCondition()
    {
        SearchCondition search = new SearchCondition();
        search.AddCondition("GroupID", this.ddlUserGroup.SelectedValue, SqlOperator.Equal, true)//班组ID
              .AddCondition("DealGroupName", this.ddlDealGroup.SelectedValue, SqlOperator.Equal, true)/**//*消缺单位*/
              .AddCondition("VisioStationID", this.ddlStation.SelectedValue, SqlOperator.Like, true)//变电站
              .AddCondition("VisioImageID", this.ddlLine.SelectedValue, SqlOperator.Like, true)/**//*馈线*/
              .AddCondition("BugNo", this.txtBugNo.Text.Trim(), SqlOperator.Like, true)/**//*编号*/
              .AddCondition("Finder", this.ddlFindUser.SelectedValue, SqlOperator.Like, true)/**//*发现人*/
              .AddCondition("CheckUser", this.ddlCheckUser.SelectedValue, SqlOperator.Like, true)//验收人
              .AddCondition("DeviceBug.BugType", this.ddlBugType.SelectedValue, SqlOperator.Equal, true)//缺陷类别
              .AddCondition("CurrentState", this.ddlCurrentState.SelectedValue, SqlOperator.Equal, true)//处理状态
              .AddCondition("FindDate", this.txtFindBeginDate.Text.Trim(), SqlOperator.MoreThanOrEqual, true)//发现日期
              .AddCondition("FindDate", this.txtFindEndDate.Text.Trim(), SqlOperator.LessThanOrEqual, true)//发现日期
              .AddCondition("EndDate", this.txtEndBeginDate.Text.Trim(), SqlOperator.MoreThanOrEqual, true)//消缺日期
              .AddCondition("EndDate", this.txtEndEndDate.Text.Trim(), SqlOperator.LessThanOrEqual, true);//消缺日期

        return search.BuildConditionSql();
    }

2. 普通做法，不使用控件，列表查询页面中的代码

Code
        private string GetCondition()
        {
            string condition = "";
            if ( this.ddlUserGroup.SelectedValue != "0")
            {
                condition += string.Format( " GroupID = {0}" , this.ddlUserGroup.SelectedValue.ToString() );
            }

            //消缺单位
            if ( this.ddlDealGroup.SelectedValue != "0")
            {
                if (condition == "")
                {
                    condition += string.Format( " DealGroupName = '{0}'" , this.ddlDealGroup.SelectedItem.Text );
                }
                else
                {
                    condition += string.Format( " And DealGroupName = '{0}'" , this.ddlDealGroup.SelectedItem.Text );
                }
            }

            
            if (this.txtStation.Text.Trim() != "")
            {
                if (condition == "")
                {
                    condition += string.Format(" Station like '%{0}%'",this.txtStation.Text.Trim() );
                }
                else
                {
                    condition += string.Format(" And Station like '%{0}%' ",this.txtStation.Text.Trim() );
                }
            }

            if (this.txtLineName.Text.Trim() != "")
            {                
                if (condition == "")
                {
                    condition += string.Format(" LineName like '%{0}%'",this.txtLineName.Text.Trim() );
                }
                else
                {
                    condition += string.Format(" And LineName like '%{0}%' ",this.txtLineName.Text.Trim() );
                }
            }

            //编号
            if (this.txtBugNo.Text.Trim() != "")
            {
                if (condition == "")
                {
                    condition += string.Format("BugNo like '%{0}%'",this.txtBugNo.Text.Trim() );
                }
                else
                {
                    condition += string.Format(" And BugNo like '%{0}%'",this.txtBugNo.Text.Trim() );
                }
            }

            //发现人
            if ( ddlFindUser.SelectedIndex >= 1 )
            {
                if (condition == "")
                {
                    condition += string.Format("Finder like '%{0}%'",ddlFindUser.SelectedValue  );
                }
                else
                {
                    condition += string.Format(" And Finder like '%{0}%'",ddlFindUser.SelectedValue );
                }
            }

            //验收人
            if ( this.ddlCheckUser.SelectedIndex >= 1 )
            {
                if (condition == "")
                {
                    condition += string.Format("CheckUser like '%{0}%'",this.ddlCheckUser.SelectedValue );
                }
                else
                {
                    condition += string.Format(" And CheckUser like '%{0}%'",this.ddlCheckUser.SelectedValue );
                }
            }

            //缺陷类别
            if (this.ddlBugType.SelectedValue.Trim() != "#")
            {
                if (condition == "")
                {
                    condition += string.Format("DeviceBug.BugType={0}",this.ddlBugType.SelectedValue.Trim() );
                }
                else
                {
                    condition += string.Format(" And DeviceBug.BugType={0}",this.ddlBugType.SelectedValue.Trim() );
                }
            }
            
            //处理状态
            if (this.ddlCurrentState.SelectedValue.Trim() != "#")
            {
                if (condition == "")
                {
                    condition += string.Format("CurrentState='{0}'",this.ddlCurrentState.SelectedValue.Trim() );
                }
                else
                {
                    condition += string.Format(" And CurrentState='{0}'",this.ddlCurrentState.SelectedValue.Trim() );
                }
            }

            //发现日期
            if (this.txtFindBeginDate.Text.Trim() != "")
            {
                if (condition == "")
                {
                    condition += string.Format("FindDate>='{0}'",this.txtFindBeginDate.Text.Trim() );
                }
                else
                {
                    condition += string.Format(" And FindDate>='{0}'",this.txtFindBeginDate.Text.Trim() );
                }
            }
            if (this.txtFindEndDate.Text.Trim() != "")
            {
                if (condition == "")
                {
                    condition += string.Format("FindDate<='{0}'",this.txtFindEndDate.Text.Trim() );
                }
                else
                {
                    condition += string.Format(" And FindDate<='{0}'",this.txtFindEndDate.Text.Trim() );
                }
            }

            //消缺日期
            if (this.txtEndBeginDate.Text.Trim() != "")
            {
                if (condition == "")
                {
                    condition += string.Format("EndDate>='{0}'",this.txtEndBeginDate.Text.Trim() );
                }
                else
                {
                    condition += string.Format(" And EndDate>='{0}'",this.txtEndBeginDate.Text.Trim() );
                }
            }
            if (this.txtEndEndDate.Text.Trim() != "")
            {
                if (condition == "")
                {
                    condition += string.Format("EndDate<='{0}'",this.txtEndEndDate.Text.Trim() );
                }
                else
                {
                    condition += string.Format(" And EndDate<='{0}'",this.txtEndEndDate.Text.Trim() );
                }
            }
            return condition;        
        }