c# - 从数据库 C# 填充数组

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() }; 
      }

如何仅将“casesYN”值设置为 Y 的“partID”插入到 case 数组中，因为现在它将在 sql 查询中插入每个“partID”。

Answer 1

我假设您不想更改 SQL 查询。

使用List<string>(requires using System.Collections.Generic) 而不是string[]因为它会更容易添加新项目：

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

如果你真的需要一个数组，你总是可以ToArray()在循环结束后调用方法：

string[] casesArray = cases.ToArray();

但它需要using System.Linq在文件的顶部。