Question

我想用asp.net从SQL数据库中检索二进制数据。但是输出中显示的数据与我插入的数据不匹配。这是我的代码：

string EQuery = "SELECT * FROM Ph_Tbl_Contacts WHERE (Contact_ID =" + Contact_ID + ")";

DataSet DSs = new DataSet();
DataTable dt = new DataTable();
DataRow dr = dt.NewRow();

DSs = DB.ExecuteQueryData(EQuery);
dt = DSs.Tables[0];

// dr = dt.NewRow();
dr = dt.Rows[0];
byte[] pic;
byte[] raw = (byte[])dr["Contact_CardImage"];
//  Session[OpenDialog.STORED_IMAGE] = raw ;

这是插入部分：

byte[] IMAGEbYTE ;
IMAGEbYTE = (byte[])(Session["SessionImage"]);
string Query = "INSERT INTO Ph_Tbl_Contacts (Contact_Name, Contact_LName, " + 
               "Contact_Company, Contact_Email, Contact_Tel, " + 
               "Contact_Mobile,Contact_CardImage,Is_Public,User_ID,Save_Date)" + 
               "VALUES (N'" + Txt_Name.Text + "', N'" + Txt_LastName.Text + "', N'" + 
               Txt_CompanyName.Text + "', N'" + Txt_Mail.Text + "', N'" + 
               Txt_Telephone.Text + "', N'" + Txt_Mobile.Text + "','" + 
               IMAGEbYTE + "','" + CheckValue + "'," + 
               Session["User_ID"] + ", N'" + DateStr + "')";

DB.ExecuteQueryNoData(Query) ;

Answer 1

好的，我们先来清理代码吧。第一件事就是修复你的INSERT代码，因为它现在很容易受到SQL注入攻击。您需要使用参数化查询：

using (var conn = new SqlConnection("Your ConnectionString comes here"))
using (var cmd = conn.CreateCommand())
{
    conn.Open();
    cmd.CommandText =
    @"INSERT INTO Ph_Tbl_Contacts 
          (Contact_Name, 
           Contact_LName, 
           Contact_Company, 
           Contact_Email, 
           Contact_Tel, 
           Contact_Mobile, 
           Contact_CardImage, 
           Is_Public, 
           User_ID, 
           Save_Date)
      VALUES 
          (@Contact_Name, 
           @Contact_LName, 
           @Contact_Company, 
           @Contact_Email, 
           @Contact_Tel, 
           @Contact_Mobile, 
           @Contact_CardImage, 
           @Is_Public, 
           @User_ID, 
           @Save_Date)
    ";
    cmd.Parameters.AddWithValue("@Contact_Name", Txt_Name.Text);
    cmd.Parameters.AddWithValue("@Contact_LName", Txt_LastName.Text);
    cmd.Parameters.AddWithValue("@Contact_Company", Txt_CompanyName.Text);
    cmd.Parameters.AddWithValue("@Contact_Email", Txt_Mail.Text);
    cmd.Parameters.AddWithValue("@Contact_Tel", Txt_Telephone.Text);
    cmd.Parameters.AddWithValue("@Contact_Mobile", Txt_Mobile.Text);
    cmd.Parameters.AddWithValue("@Contact_CardImage", IMAGEbYTE);
    cmd.Parameters.AddWithValue("@Is_Public", CheckValue);
    cmd.Parameters.AddWithValue("@User_ID", Session["User_ID"]);
    cmd.Parameters.AddWithValue("@Save_Date", DateStr); 
    cmd.ExecuteNonQuery();
}

值得一提的是，如果数据库中的Save_Date列为datetime，则应为参数传递DateTime的实例，而不是尝试将其转换为string = ＆GT; DateStr必须是DateTime。

好了，既然您已将记录正确地插入数据库，您就可以阅读它：

using (var conn = new SqlConnection("Your ConnectionString comes here"))
using (var cmd = conn.CreateCommand())
{
    conn.Open();
    cmd.CommandText = 
    @"SELECT
          Contact_CardImage
      FROM 
          Ph_Tbl_Contacts 
      WHERE 
          Contact_ID = @Contact_ID
    ";
    cmd.Parameters.AddWithValue("@Contact_ID", Txt_Name.Text); 
    using (var reader = cmd.ExecuteReader())
    {
        if (reader.Read())
        {
            byte[] raw = (byte[])reader.Items["Contact_CardImage"];
            // TODO: do something with the raw data
        }
    }
}

使用asp.net从SQL数据库中检索二进制数据

1 个答案: