在指定的DataTable里多关键字搜索多个列

/**//// <summary>
        /// 搜索方法
        /// </summary>
        /// <param name="toFindDt">要搜索的DataTable</param>
        /// <param name="PKIDColumnName">表的标识列</param>
        /// <param name="ColumnHt">HashTable表</param>
        /// <returns></returns>
        protected string SearchFiles(DataTable toFindDt,string PKIDColumnName, Hashtable ColumnHt)
        {
            //行数
            string[] ArraryPKID =  new string[toFindDt.Rows.Count];
            for(int i=0; i<toFindDt.Rows.Count; i++)
            {
                ArraryPKID[i] = "";
            }
            string searchKey = "";
            string cloumnName = "";
            bool bfind;

            for(int i=0; i<toFindDt.Rows.Count; i++)
            {
                //bfind = false;
                bfind = true;

                寻找各个字段ColumnHt里的是否有关键字#region 寻找各个字段ColumnHt里的是否有关键字
                //寻找各个字段ColumnHt里的是否有关键字
                foreach (DictionaryEntry myDE in ColumnHt) 
                {                    
                    cloumnName = myDE.Key.ToString();
                    searchKey = myDE.Value.ToString();

                    ***下面开始对关键詞searchKey进行拆分***#region ***下面开始对关键詞searchKey进行拆分***        
                    string[] arrkey = new string[10];
                    for(int j=0;j<10;j++)
                    {
                        arrkey[j]="";
                    }
                    int pos=0;
                    char[] ch = new char[100];
                    ch = searchKey.ToCharArray(0,searchKey.Length);

                    for(int j=0;j<searchKey.Length;j++)
                    {
                        if(ch[j]!=' '&&ch[j]!='　'&&ch[j]!=',')
                        {
                            arrkey[pos] = arrkey[pos]+ch[j].ToString();
                    
                        }
                        else
                        {
                            if(ch[j+1]!=' '&&ch[j+1]!='　'&&ch[j+1]!=',')
                            {
                                pos++;
                            }
                        }
                
                        if(pos==10)
                        {
                            PopMessage("对不起，您输入的关键词不能超过10个!");
                            return null;
                        }
                    }
                    #endregion
            
                    //找到关键词后，开始进行搜索
                    int len = pos+1;
                    
                    string findStr = "";
                    findStr = toFindDt.Rows[i][cloumnName].ToString();
                
                    //关键词的数量
                    for(int j=0;j<len;j++)
                    {                        
                        //找到字符串
//                        if(findStr.IndexOf(arrkey[j],0,findStr.Length) > -1)
//                        {
//                            bfind = true;                            
//                        }
                        if(findStr.IndexOf(arrkey[j],0,findStr.Length) == -1)
                        {
                            bfind = false;
                            break;
                        }
                    }                     
                }//end foreach
                //找到结果，这样找是或的结果
                if(bfind == true)
                {
                    ArraryPKID[i] = toFindDt.Rows[i][PKIDColumnName].ToString();
                }
                #endregion

            }//end for
            

            string PKIDS = "";
            for(int i=0; i<ArraryPKID.Length; i++)
            {
                if( ArraryPKID[i].ToString() != "")
                {
                    PKIDS += ArraryPKID[i] + ",";
                }
            }

            if(PKIDS.Length > 0)
            {
                PKIDS = PKIDS.Substring(0,PKIDS.Length-1);
            }            
            return PKIDS;
        }
   使用示例：

                    Hashtable columnHt = new Hashtable();
                    if(txtContent.Text.Trim() != "")
                    {
                        columnHt.Add("SerialNum",txtContent.Text.Trim());
                    }
                    if(txtTitle.Text.Trim() != "")
                    {
                        columnHt.Add("Title",txtTitle.Text.Trim());
                    }    
                    if(columnHt.Count > 0)
                    {
                        //把所有的FileID取到，“,”隔开
                        string pkids = "";
                        pkids = this.SearchFiles(Sourcedt,"PKID",columnHt);
                        if(pkids != "")
                        {
                            string sqlStr = String.Format("select * from MyTable where PKID in {0}",pkids);
                            //取结果……
                        }
                    }

   呵呵,这个是或的关系,很容易改成与的关系.请高手赐教!