Question

我正试图从阵列中找回2个独特的图像。现在我正在刷新页面，直到我得到2个独特的图像。这不太理想。如何修改此代码以备份2个独特的图像，而无需刷新页面直到它为止。

我可以在此图层中执行此操作，还是需要检查数据层中的唯一编号？

 Picture dlPicture = new Picture();
        DataTable DTPictures = dlPicture.GetRandomPicture();
        Picture dlPicture2 = new Picture();
        DataTable DTPictures2 = dlPicture2.GetRandomPicture();



        // the variables to hold the yes and no Id's for each set
        string firstNoPicId = "";
        string firstYesPicId = "";
        string secondNoPicId = "";
        string secondYesPicId = "";

        foreach (DataRow row in DTPictures.Rows)
        {
            firstYesPicId = row["PicID"].ToString();
            secondNoPicId = firstYesPicId;
            FirstPicMemberNameLabel.Text = row["MemberName"].ToString();
            FirstPicLink.ImageUrl = "Pictures/" + row["PicLoc"];

        }

        foreach (DataRow row in DTPictures2.Rows)
        {
            secondYesPicId = row["PicID"].ToString();
            firstNoPicId = secondYesPicId;
            SecondPicMemberNameLabel.Text = row["MemberName"].ToString();
            SecondPicLink.ImageUrl = "Pictures/" + row["PicLoc"];

        }
        if (firstYesPicId != secondYesPicId)
        {

            FirstPicLink.PostBackUrl = "default.aspx?yesId=" + firstYesPicId + "&noId=" + firstNoPicId;
            SecondPicLink.PostBackUrl = "default.aspx?yesId=" + secondYesPicId + "&noId=" + secondNoPicId;
        }
        else
        {
            Response.Redirect("Default.aspx");
        }

Answer 1

有两种非常明显的方法来处理这个

添加重载dlPicture.GetRandomPicture(int picID)这将接受一个ID，以便它不会返回已经使用过的picID
重新构建代码，使其循环到secondYesPicId != firstYesPicId

像

 secondYesPicId = firstYesPicId;
 while (firstYesPicId == secondYesPicId)
 {  DataTable DTPictures2 = dlPicture2.GetRandomPicture();

     foreach (DataRow row in DTPictures2.Rows)
    {
        secondYesPicId = row["PicID"].ToString();
        SecondPicMemberNameLabel.Text = row["MemberName"].ToString();
        SecondPicLink.ImageUrl = "Pictures/" + row["PicLoc"];

    }
 }

Answer 2

也许更好的解决方案是在datalayer.GetRandomPicture中添加代码以确保它不能连续两次返回相同的图片？

在这个Picture类中添加一个LastRandomPictureID变量并在你的查询上做一个'WHERE NOT ID = LastRandomPictureID'（你可能想让它更健壮一些，以处理只有1张图片存在的情况）。

Answer 3

var rnd = new Random();
int randomPicIndex1 = rnd.Next(numOfPictures);
int randomPicIndex2;
do {
    randomPicIndex2 = rnd.Next(numOfPictures);
} while (randomPicIndex1 == randomPicIndex2);

然后使用这些索引从表中获取随机行。

DataRow row1 = DTPictures.Rows[randomPicIndex1];
DataRow row2 = DTPictures.Rows[randomPicIndex2];

从数组中返回2个随机图像

3 个答案: