Question

我有数据库表，其中我有两列名称picid和pic1..in我的pic1列我有三个数据..现在想要使用sqldatareader重新检索数据我得到列数据的顶部..how获取该列的所有数据并将其用于进一步的目的..

我的代码

protected void Page_Load(object sender, EventArgs e)
{
    string con = " ";
    con = ConfigurationManager.ConnectionStrings["ConnectionString"].ToString();
    SqlConnection objsqlconn = new SqlConnection(con);
    objsqlconn.Open();
    SqlCommand cmd = new SqlCommand("SELECT * From pictable", objsqlconn);
    SqlDataReader grpIDreader = cmd.ExecuteReader();
    grpIDreader.Read();
    string path = grpIDreader["pic1"].ToString();
    //slide.Attributes["style"] = String.Format("background-image:url('{0}')", path);
    image1.Attributes["src"] = String.Format("{0}", path);
    image2.Attributes["src"] = String.Format("{1}", path);
    image3.Attributes["src"] = String.Format("{2}", path);
}

我想获取保存在数据库的pic1列中的路径。我收到此错误“System.FormatException：索引（从零开始）必须大于或等于零且小于参数列表的大小。” 我也尝试了同样的错误

    protected void Page_Load(object sender, EventArgs e)
{
    string con = " ";
    con = ConfigurationManager.ConnectionStrings["ConnectionString"].ToString();
    SqlConnection objsqlconn = new SqlConnection(con);
    objsqlconn.Open();
    SqlCommand cmd = new SqlCommand("SELECT * From pictable", objsqlconn);
    SqlDataReader grpIDreader = cmd.ExecuteReader();
    string[] path={"","",""};
    int i = 0;
    while(grpIDreader.Read())
    {
         path[i++] = grpIDreader["pic1"].ToString();

    }


    //slide.Attributes["style"] = String.Format("background-image:url('{0}')", path);
    image1.Attributes["src"] = String.Format("{0}", path[0]);
    image2.Attributes["src"] = String.Format("{1}", path[1]);
    image3.Attributes["src"] = String.Format("{2}", path[2]);
}

Answer 1

您收到字符串格式错误，而不是数据库错误：

image1.Attributes["src"] = String.Format("{0}", path); //This works, as 0 indicates the first argument you are passing in
image2.Attributes["src"] = String.Format("{1}", path); //This won't work, as you are asking for the second argument, which doesn't exist

Answer 2

使用以下内容获取每一行

using (SqlDataReader grpIDreader = cmd.ExecuteReader())
{
 while (grpIDreader.Read()) //.Read() advances to the next row and returns false if there are no more
{
string path = grpIDreader["pic1"].ToString();
//other stuff here
}
}

也

而不是

image1.Attributes["src"] = String.Format("{0}", path[0]);

这样做

image1.Attributes["src"] = path[0];

如何使用SqlDataReader从数据库中检索多个数据？

2 个答案: