Question

我也知道这个（某种）问题已被多次提出并回答。我以前曾经问过这个问题。但我还是成功了。如何在特定员工ID的图像控件中显示图像...继承我的代码：

` 绑定（） GridView1.Visible =“True”

    Dim strQuery As String = "SELECT Image FROM EmployeeTable WHERE EmployeeID =@EmployeeID"
    Dim cmd As SqlCommand = New SqlCommand(strQuery)
    cmd.Parameters.Add("@EmployeeID", SqlDbType.Int).Value() = Convert.ToInt32(Request.QueryString("ImageID"))
    Dim dt As DataTable = GetData(cmd)
    If dt IsNot Nothing Then
        **Dim bytes() As Byte = CType(dt.Rows(1)("Image"), Byte())**
        Response.Buffer = True
        Response.Charset = ""
        Response.Cache.SetCacheability(HttpCacheability.NoCache)
        Response.ContentType = dt.Rows(0)("ContentType").ToString()
        Response.AddHeader("content-disposition", "attachment;filename=" + dt.Rows(1)("Name").ToString())
        Response.BinaryWrite(bytes)
        Response.Flush()
        Response.End()
    End If`

以粗体显示错误。 “位置1没有排”...... 实际上我想获取（显示）特定员工ID的图像。它如何与行位置有关？我不知道为什么我写了那行代码。无论如何，我知道有些人可以帮助我，所以我提前感谢他们......

好的，这是我将代码添加到数据库的代码。这很好。

 Dim imageData As Byte() = New Byte(FileUpload1.FileContent.Length) {}
    FileUpload1.FileContent.Read(imageData, 0, Convert.ToInt32(FileUpload1.FileContent.Length))

    Dim con As New SqlConnection(System.Configuration.ConfigurationManager.AppSettings("ConnectionString").ToString)
    con.Open()
    If EmployeeIDTextBox.Text = "" Then
        MsgBox("Please Enter EmployeeID to Add Photo")
    Else
        Dim com As New SqlCommand("UPDATE EmployeeTable SET IMAGE = @IM where EmployeeID='" & EmployeeIDTextBox.Text & "'", con)
        Dim filePath As String = Server.MapPath(FileUpload1.FileName)
        'Dim imageData As Byte() = File.ReadAllBytes(filePath)
        com.Parameters.AddWithValue("@IM", imageData)
        com.ExecuteNonQuery()
        MsgBox("File Saved Successfully!")
    End If
End Sub

现在这是我的检索代码＆amp;在图像控件中显示相同的图像......

  bind()
    GridView1.Visible = "True"
    'If Request.QueryString("ImageID") IsNot Nothing Then
    Dim strQuery As String = "SELECT Image FROM EmployeeTable WHERE EmployeeID =@EmployeeID"
    Dim cmd As SqlCommand = New SqlCommand(strQuery)
    cmd.Parameters.Add("@EmployeeID", SqlDbType.Int).Value() = Convert.ToInt32(Request.QueryString("Image"))
    Dim dt As DataTable = GetData(cmd)
    If dt IsNot Nothing Then
        Dim bytes() As Byte = CType(dt.Rows(0)("Image"), Byte())
        Response.Buffer = True
        Response.Charset = ""
        Response.Cache.SetCacheability(HttpCacheability.NoCache)
        Response.ContentType = dt.Rows(0)("ContentType").ToString()
        Response.AddHeader("content-disposition", "attachment;filename=" + dt.Rows(1)("Name").ToString())
        Response.BinaryWrite(bytes)
        Response.Flush()
        Response.End()
    End IF

这不起作用......

Answer 1

数组索引从0开始

使用

Dim bytes() As Byte = CType(dt.Rows(0)("Image"), Byte())

你怎么不知道为什么写这个？

您拥有的代码将提示用户将图像文件保存在他的电脑上它不会在图像控件中显示图像。

Answer 2

你可以使用Http Handler并在ProcessRequest()

中使用以下代码

int Id = Convert.ToInt32(Request.QueryString["ImgId"]);
using (var conn = new SqlConnection(connectionString))
using (var command = new SqlCommand(
"SELECT ImageFile FROM ImageTable WHERE ImageId = @ImgId", conn))
{
    command.Parameters.Add("@ImgId", SqlDbType.Int).Value = Id ;
conn.Open();
Response.ContentType = "image/gif"; //u can set it per ur requirement
Response.BinaryWrite((byte[]) command.ExecuteScalar());
}

然后在页面中使用图片：

  <asp:Image id="Img_Db" runat="server" ImageUrl="Image.ashx?ImgId=1"/>

如何从数据库中显示图像？

2 个答案: