C＃使用列表和文本文件执行SQL查询然后导出

Question

Scenario: I have a list table being populated from a combobox. That list table can have up to 50 things listed in it(whats listed in the listbox is column names). Tricky part: I have a text file that matches one field in the sql table. X1,X2,X3 are the listbox items.

So i basically need:

select <line in text file>, from <blah> where id = object_id('table')  
export <x2>,<x3>,<x4>,<x5>,<x6>,C:\Comma.text

I dont need help making the listbox, or the SQL connection.

Just basically how do i list my listbox in strings (no matter what the order selected is to represent whatever was selected in that order, and the SQL command to match based on textfile and export it.)

I know this one is going to be a pain. Thanks in advanice

Answer 1

Your question isn't very clear... does the text file contain the primary key values for rows in the table?

If that is the case, your SQL pseudo code will look like so:

select <selectedColumn1>, <selectedColumn2>,...  
from yourTable  
where primarykeyColumn in (<yourTextFileValues>)  

As to how to get selected items from a listbox to a string, and format a SQL statement to only select those rows from the database to export, here is one way:

string[] selectedColumns = new string[myListBox.SelectedItems.Count];
for(int i = 0; i < myListBox.SelectedItems.Count; i++)
{
    selectedColumns[i] = myListBox.SelectedItems[i].ToString();
}
string exportColumns = string.Join(",", selectedColumns);

//format your sql statement
string sqlStatement = string.Format("select {0} from YourTable WHERE blah=blah2", 
                                     exportColumns);

If everything in the list box is considered 'selected' for export, then just replace myListBox.SelectedItems with myListBox.Items