如何將圖像的BLOB保存到sql數據庫中而不保存到文件系統中？

Question

我一直在試圖發現的是，如何將圖像的BLOB存儲到我的數據庫中，而不必先將它保存到文件系統中，直接從服務器的內存中保存。

我使用一個sql服務器和其他形式的信息，我有2個圖像需要存儲在數據庫中。我還想知道如何將它們讀出來並將它們轉換回圖像。

在數據庫我有「縮略圖」，它是類型「圖像」。如果我沒有錯，那應該是正確的。

對於圖像上傳我用下面的ASP控制：

<asp:FileUpload ID="_imageUpload" runat="server" /> 

，因爲我很新的使用數據庫與網站一起特別是我還從來沒有做過這樣的事。

哦，對不起，如果這個問題已被問及已回答。

在此先感謝！

[編輯]

我的整個代碼：

protected void _uploadImageBtn_Click(object sender, EventArgs e) 
{ 
    string extension; 

    // checks if file exists 
    if (!_imageUpload.HasFile) 
    { 
     _resultLbl.Text = "Please, Select a File!"; 
     return; 
    } 

    // checks file extension 
    extension = System.IO.Path.GetExtension(_imageUpload.FileName).ToLower(); 

    if (!extension.Equals(".jpg") && !extension.Equals(".jpeg") && !extension.Equals(".png")) 
    { 
     _resultLbl.Text = "Only image files (.JPGs and .PNGs) are allowed."; 
     return; 
    } 

    // checks if image dimensions are valid 
    if (!ValidateFileDimensions(140, 152)) 
    { 
     _resultLbl.Text = "Maximum allowed dimensions are: width 1520px and height <= 140px."; 
     return; 
    } 

    int fileLen; 
    string displayString = ""; 

    // Get the length of the file. 
    fileLen = _imageUpload.PostedFile.ContentLength; 

    // Create a byte array to hold the contents of the file. 
    byte[] input = new byte[fileLen - 1]; 
    input = _imageUpload.FileBytes; 

    // Copy the byte array to a string. 
    for (int loop1 = 0; loop1 < fileLen; loop1++) 
    { 
     displayString = displayString + input[loop1].ToString(); 
    } 

    try 
    { 

     SqlConnection sqlCn = new SqlConnection("Data Source=localhost;Initial Catalog=database;User ID=user;Password=pw"); 

     string qry = "INSERT INTO Project (thumbnail) VALUES (@thumbnail)"; 

     SqlCommand sqlCom = new SqlCommand(qry, sqlCn); 

     sqlCom.Parameters.Add("@thumbnail", SqlDbType.Image, input.Length).Value = input; 

     sqlCn.Open(); 
     sqlCom.ExecuteNonQuery(); 
     sqlCn.Close(); 

    } 

    catch (Exception) 
    { 
     (...) 
    } 
} 

public bool ValidateFileDimensions(int aHeight, int aWidth) 
{ 
    using (System.Drawing.Image image = System.Drawing.Image.FromStream(_imageUpload.PostedFile.InputStream)) 
    { 
     return (image.Height == aHeight && image.Width == aWidth); 
    } 
} 

Answer 1

您可以保存從FileUpload.FileBytes返回字節數組。

if(_imageUpload.HasFile) 
{ 
byte[] imageData = _imageUpload.FileBytes; 

using(SqlConnection sqlCn = new SqlConnection("Server=localhost;database=databaseName;uid=userName;pwd=password")) 
    { 
    string qry = "INSERT INTO Project (thumbnail) VALUES (@thumbnail)"; 
    using(SqlCommand sqlCom = new SqlCommand(qry, sqlCn)) 
    { 
     sqlCom.Parameters.Add("@thumbnail", 
           SqlDbType.Image, 
           imageData.Length).Value=imageData; 
     sqlCn.Open(); 
     sqlCom.ExecuteNonQuery(); 
     sqlCn.Close(); 
    } 
    } 
} 

編輯：

protected void _uploadImageBtn_Click(object sender, EventArgs e) 
{ 
    string extension; 

    // checks if file exists 
    if (!_imageUpload.HasFile) 
    { 
     _resultLbl.Text = "Please, Select a File!"; 
     return; 
    } 

    // checks file extension 
    extension = System.IO.Path.GetExtension(_imageUpload.FileName).ToLower(); 

    if (!extension.Equals(".jpg") && !extension.Equals(".jpeg") && !extension.Equals(".png")) 
    { 
     _resultLbl.Text = "Only image files (.JPGs and .PNGs) are allowed."; 
     return; 
    } 

    // checks if image dimensions are valid 
    if (!ValidateFileDimensions(140, 152)) 
    { 
     _resultLbl.Text = "Maximum allowed dimensions are: width 1520px and height <= 140px."; 
     return; 
    } 


    byte []input = _imageUpload.FileBytes; 
    SqlConnection sqlCn = new SqlConnection("Data Source=localhost;Initial 
           Catalog=database;User ID=user;Password=pw"); 

    string qry = "INSERT INTO Project (thumbnail) VALUES (@thumbnail)"; 
    SqlCommand sqlCom = new SqlCommand(qry, sqlCn); 
    sqlCom.Parameters.Add("@thumbnail", SqlDbType.Image, input.Length).Value = input; 
    sqlCn.Open(); 
    sqlCom.ExecuteNonQuery(); 
    sqlCn.Close(); 
}