從數據庫 C# 填充數組

Question

SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["cnnFinalProject"].ToString());
SqlCommand cmd = new SqlCommand(@"SELECT c.partID, p.name, p.categoryID, p.price, p.image, p.subCategoryID, 
                                        (CASE WHEN categoryID = 1 THEN 'Y' ELSE 'N' END) AS casesYN,
                                        (CASE WHEN categoryID = 3 THEN 'Y' ELSE 'N' END) AS OSYN,
                                        (CASE WHEN categoryID = 7 THEN 'Y' ELSE 'N' END) AS HDDYN,
                                        (CASE WHEN subCategoryID = 1 THEN 'Y' ELSE 'N' END) AS powerYN,
                                        (CASE WHEN subCategoryID = 2 THEN 'Y' ELSE 'N' END) AS processorYN,
                                        (CASE WHEN subCategoryID = 3 THEN 'Y' ELSE 'N' END) AS moboYN,
                                        (CASE WHEN subCategoryID = 4 THEN 'Y' ELSE 'N' END) AS memoryYN,
                                        (CASE WHEN subCategoryID = 5 THEN 'Y' ELSE 'N' END) AS graphicsYN,
                                        (CASE WHEN subCategoryID = 6 THEN 'Y' ELSE 'N' END) AS opticalYN,
                                        (CASE WHEN subCategoryID = 7 THEN 'Y' ELSE 'N' END) AS soundYN
                                        FROM configuration c JOIN parts p ON p.partID = c.partID
                                        WHERE c.customID = @ID", conn);
      conn.Open();
      SqlDataReader dr = cmd.ExecuteReader();
      while (dr.Read())
      {
        string[] cases = { dr["partID"].ToString() }; 
      }

如何僅將“casesYN”值設置為 Y 的“partID”插入到案例數組中，因為現在它會在 sql 查詢中插入每個“partID”。

Answer 1

我假設您不想更改 SQL 查詢。

使用List<string> （需要using System.Collections.Generic ）而不是string[]因為向其中添加新項目會更容易：

var cases = new List<string>();
while (dr.Read())
{
    if(dr["casesYN"].ToString() == "Y")
        cases.Add(dr["partID"].ToString()); 
}

如果你真的需要一個數組，你總是可以在循環結束后調用ToArray()方法：

string[] casesArray = cases.ToArray();

但它需要在文件頂部using System.Linq 。