Question

我有两个dataTable，一个包含从数据库填充的书名和描述，另一个将包含搜索结果的行，关键字值是一个变量。

我想搜索第一个数据表，如果标题或描述包含变量，如果是，我想将行添加到新的DataTable。

我尝试了以下代码，但它不起作用，我在结果上得到异常，如果我搜索精确变量的标题，我在gridview中什么也得不到。

DataTable books = new DataTable();
DataTable searchresults = new DataTable();
DataRow[] results;

 foreach (var v in keywordsarray)
 {
    results = books.Select("BookTitle like '"+v+"'or BookDescription like'"+v+"'");
 }

foreach (DataRow v in results)
{
    searchresults.ImportRow(v);
}

  //the grid view
 search.DataSource = searchresults;
 search.DataBind();

Answer 1

在将行导入clone i.e. the structure of source datatable之前，您没有创建destination datatable 以下是代码如何实现这一目标：

DataTable books = new DataTable();
DataRow[] results = default(DataRow[]); //initialized with default
string[] keywordsarray = new string[] { "a", "b" }; //example

books.Columns.Add("BookTitle"); //example added column
books.Columns.Add("BookDescription"); //example added column
books.AcceptChanges();

books.Rows.Add("abc", "def"); //example added row
books.Rows.Add("a", "c");   //example added row

//fill books datatable from database 

DataTable dtSearchResult = books.Clone();   //copy structure from source datatable

foreach (var v in keywordsarray)
{
    results = books.Select("BookTitle like '%" + v + "%' or BookDescription like '%" + v + "%'");

    foreach (DataRow dr in results)
    {
        //must be criteria here to check for duplicate rows in dtSearchResult.
        dtSearchResult.ImportRow(dr);
    }
}          

dtSearchResult.AcceptChanges();

 //the grid view
search.DataSource = dtSearchResult;
search.DataBind();

Answer 2

以下是我认为您需要让代码看起来以获取数据并避免异常：

List<string> keywordsarray = new List<string>();

/*do something to fill your list with the keyword data*/

DataTable books = new DataTable();
DataTable searchresults = new DataTable();
DataRow[] results;

 foreach (string keyword  in keywordsarray)
 {
    results = books.Select("BookTitle like '"+keyword+"' or BookDescription like'"+keyword+"'");
    foreach (DataRow dr in results)
    {
       searchresults.ImportRow(dr);
    }
 }
 //the grid view
 search.DataSource = searchresults;
 search.DataBind();

如果您想要进行非完全匹配，则需要将％'添加到select中，如另一篇文章所述：

results = books.Select("BookTitle like '%"+keyword+"%' or BookDescription like'%"+keyword+"%'");

Answer 3

如果您使用的是arraylist，为什么不使用以下内容：

foreach (string str in keywordsarray) 
 { 
    //use str in this case, which may resolve the exception 
 }

在datatable中搜索并将行结果添加到另一个数据表中？

3 个答案: