更新图像jpg时出错

Question

我收到以下错误：

  

“无法将参数值从位图转换为byte []。”当我尝试更新记录时，图像没有得到更新。

这是我的代码：

private void btnupdate_Click(object sender, EventArgs e)
{
    try
    {
        conn.Close();
        conn.Open();

        MemoryStream stream = new MemoryStream();
        pb1.Image.Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg);
        byte[] pic = stream.ToArray();

        SqlCommand command = new SqlCommand ("Update Stock_Jewelry  set Stock_Type = @Stock_Type, Stock_No = @Stock_No , Quantity = @Quantity, Item_Description = @Item_Description, Item_Type = @Item_Type, No_of_Gems = @No_of_Gems, Gem_Type = @Gem_Type, Image = @Image WHERE  ID = @ID",conn);

        command.Parameters.Add("@ID", SqlDbType.VarChar).Value = txt_ID.Text;
        command.Parameters.Add("@Stock_Type", SqlDbType.VarChar).Value = Stock_Type.Text;
        command.Parameters.Add("@stock_no", SqlDbType.NVarChar).Value = txt_stock_no.Text;
        command.Parameters.Add("@Quantity", SqlDbType.Int).Value = txt_qty.Text;
        command.Parameters.Add("@Item_Description", SqlDbType.NVarChar).Value = combo_itemk_description.Text;
        command.Parameters.Add("@Item_Type", SqlDbType.NVarChar).Value = combo_item_type.Text;
        command.Parameters.Add("@No_of_Gems", SqlDbType.Int).Value = txt_no_of_gems.Text;
        command.Parameters.Add("@Gem_Type", SqlDbType.NVarChar).Value = txt_gem_type.Text;
        command.Parameters.Add("@Image", SqlDbType.Image).Value = pb1.Image;
        /*
          using (MemoryStream ms = new MemoryStream())
          {
          pb1.Image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
          command.Parameters.Add("@Image", SqlDbType.Image).Value = ms.ToArray();
          }
          command.ExecuteNonQuery();*/

        MessageBox.Show("You've updated successfully!", "Successful Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
        conn.Close();
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message, "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
    conn.Close();

    this.Close();
}

Answer 1

这对我有用......

private void btnupdate_Click(object sender, EventArgs e)
{
    try
    {
        conn.Close();
        conn.Open();

        SqlCommand command = new SqlCommand ("Update Stock_Jewelry  set Stock_Type = @Stock_Type, Stock_No = @Stock_No , Quantity = @Quantity, Item_Description = @Item_Description, Item_Type = @Item_Type, No_of_Gems = @No_of_Gems, Gem_Type = @Gem_Type, Image = @Image WHERE  ID = @ID",conn);

        command.Parameters.Add("@ID", SqlDbType.VarChar).Value = txt_ID.Text;
        command.Parameters.Add("@Stock_Type", SqlDbType.VarChar).Value = Stock_Type.Text;
        command.Parameters.Add("@stock_no", SqlDbType.NVarChar).Value = txt_stock_no.Text;
        command.Parameters.Add("@Quantity", SqlDbType.Int).Value = txt_qty.Text;
        command.Parameters.Add("@Item_Description", SqlDbType.NVarChar).Value = combo_itemk_description.Text;
        command.Parameters.Add("@Item_Type", SqlDbType.NVarChar).Value = combo_item_type.Text;
        command.Parameters.Add("@No_of_Gems", SqlDbType.Int).Value = txt_no_of_gems.Text;
        command.Parameters.Add("@Gem_Type", SqlDbType.NVarChar).Value = txt_gem_type.Text;

        using (MemoryStream ms = new MemoryStream())
        {
          pb1.Image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
          command.Parameters.Add("@Image", SqlDbType.Image).Value = ms.ToArray();
        }
        command.ExecuteNonQuery();

        MessageBox.Show("You've updated successfully!", "Successful Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
        conn.Close();
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message, "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
    conn.Close();

    this.Close();
}

Answer 2

1. 将db中的字段类型更改为 - ＆gt; VARBINARY（MAX）

2. 更改此行：command.Parameters.Add（＆＃34; @ Image＆＃34;，SqlDbType.VarBinary）.Value = pic;

3. 从db读取时使用此方法：

   public Image ByteArrayToImage(byte[] byteArray) { try { MemoryStream ms = new MemoryStream(byteArray); return Image.FromStream(ms); } catch (Exception) { return null; } }