Question

我正在尝试创建一个类似于MS Access使用的查询生成器。我有一个绑定到DataGridView的数据。当用户激活表单时，他或她可以在DataGridView中输入值，然后将其反映在数据表中。我想从数据表中检索这些值，但是有一个问题：

每一行都会创建自己的＆＃39; AND＆＃39;语句，当它移动到一个新行时，它会添加一个＆＃39; OR＆＃39;。例如：

XXX OR RRR |        |    CCC       |             |  DDD          |
-----------|--------|--------------|-------------|-------------- |
           |        |     BBB      |             |               |

因此，下表的用户输入的最终结果应为：

（（XXX OR RRR）和CCC AND DDD）或BBB

这与MS Access中查询的设计视图非常相似。

我尝试过使用GetValues（）方法，但由于某些原因似乎没有触发。以下是我的代码片段：

    // Build string and then run to test and have user scroll through data  'test' 'run' after they view save,          dynamic or showing up, character check
    private void auto_Click(object sender, EventArgs e) 
    {
        DataTable changed = new DataTable();
        changed =  dt.GetChanges();

        where_Clause = "";
        row_Count = auto_GridView1.Rows.Count;  // SHould the datagridview or the data rows be counted
        column_count = auto_GridView1.Columns.Count;

        for (int i = 0; i < row_Count; i++)  
        {  
            // where_Clause += (row_Count - 1) ? "AND" + auto_GridView1[i, j].ToString() : string.Empty;
            if (i > 0)
            {                    
                where_Clause = where_Clause + " OR";                
            }

            for (int j = 0; j < column_count; j++)
            {                   
                // Need to see if the Value of the cell changed. If so must validate
                where_Clause += (i < column_count - 1) ?  "AND" + dt.Rows[i][j].ToString() : string.Empty;   // USE DATA TABLE  
            }
        }

这循环遍及整个表格，基本上连接了一大堆＆＃39; AND＆＃39;有什么想法吗？

Answer 1

我明白了。我用一个输入循环遍历每个单元格并将其转换为简单放置的字符串。我打电话给其他职能部门来实现其他目标。

private void auto_Click(object sender, EventArgs e)  // Build string and then run to test and have user scroll through data  'test' 'run' after they view save,          dynamic or showing up, character check
    {

        //DataTable changed = new DataTable();
        // changed =  dt.GetChanges();



        where_Clause = "((";
        row_Count = auto_GridView1.Rows.Count;                // SHould the datagridview or the data rows be counted
        column_count = auto_GridView1.Columns.Count;



        for (int i = 0; i < row_Count - 1; i++)     // Begins by selecting the row
        {

            char[] MyChar = { 'A', 'N', 'D', ' ' };   
             where_Clause = where_Clause.TrimEnd(MyChar);                // Trims in the loop however doesnt pick up the last AND Still leaves last one

            if (i > 0 )    // Adds the 'OR' after Row [0] b/c 'OR' isnt needed at row[0]
            {
              where_Clause = where_Clause + "  ) OR ( ";    

            }

            for (j = 0; j < column_count - 1; j++)     // Loops through all the columns in a given row 
            {


                if (dt.Rows[i][j].ToString() != "")        // Checks to see if there is a value in the box. If so it adds it to the Clause

                {
                     header = "";
                     string current_cell = "";


                    header = get_correct_header(j);  // Use j to get the header ]

                    current_cell = dt.Rows[i][j].ToString(); // gets the current selection

                    current_cell = insert_correctHeader(current_cell, header); // reads throught he string pickling up the necessary symbols and inserting in the correct header name 

                    where_Clause += (i < column_count - 1) ?   current_cell + " AND " : string.Empty;   // USE DATA TABLE


                }




            }


        }


        char[] Mychar2 = { 'A', 'N', 'D', ' ' };           // Trim again to get rid of that final AND 
        where_Clause = where_Clause.TrimEnd(Mychar2); 
        where_Clause = where_Clause + "))";





        MessageBox.Show(where_Clause);  // We have the where clause here must be tested to see if it works

如何在Datatable中检索仅更改的值并将它们放入唯一的字符串中

1 个答案: