参数无效错误 [英] Parameter is not valid error
问题描述
//将图像保存到sql server 2008的代码r2 //////
byte [] img = null;
FileStream fs = new FileStream（imgLoc，FileMode.Open，FileAccess.Read）;
BinaryReader br = new BinaryReader（fs）;
img = br.ReadBytes（（int）fs.Length）;
string conn =data source = .;初始目录= RMSDB ; user = sa; password = ibs;;
SqlConnection con = new SqlConnection（conn）;
con.Open（）;
string cmdd = String.Format（INSERT INTO Employees（Emp_Pic_ImageData）VALUES（'{0}'），@ img）;
SqlCommand cmd = new SqlCommand（ cmdd，con）;
cmd.Parameters.Add（new SqlParameter（@ img，img））;
int tempss = cmd.ExecuteNonQuery（）;
//从sql server审查图像的代码//////////// < br $>
string sql = String.Format（从雇员那里选择Emp_Pic_ImageData，其中Emp_Id ='{0}'，TxtBoxId.Text）;
SqlCommand cmd = new SqlCommand（sql，con）;
SqlDataReader reader = cmd.ExecuteReader（）;
reader.Read（）;
if（reader.HasRows）
{
byte [] img =（byte []）（reader [0]）;
if（img == null）
{
PicboxEmployee.Image = null;
}
else
{
MemoryStream mstrm = new MemoryStream（img）;
PicboxEmployee.Image = new System.Drawing.Bitmap（mstrm ）; //参数错误无效。
}
}
else
{
MessageBox.Show（这不存在）;
}
//code for saving image into sql server 2008 r2//////
byte[] img = null;
FileStream fs = new FileStream(imgLoc,FileMode.Open,FileAccess.Read);
BinaryReader br=new BinaryReader(fs);
img = br.ReadBytes((int)fs.Length);
string conn = "data source=.;Initial catalog=RMSDB;user=sa;password=ibs;";
SqlConnection con = new SqlConnection(conn);
con.Open();
string cmdd = String.Format("INSERT INTO Employees (Emp_Pic_ImageData) VALUES('{0}')", @img);
SqlCommand cmd = new SqlCommand(cmdd, con);
cmd.Parameters.Add(new SqlParameter("@img",img));
int tempss = cmd.ExecuteNonQuery();
//code for retrival of image from sql server////////////
string sql = String.Format("Select Emp_Pic_ImageData From Employees where Emp_Id='{0}'", TxtBoxId.Text);
SqlCommand cmd = new SqlCommand(sql, con);
SqlDataReader reader = cmd.ExecuteReader();
reader.Read();
if (reader.HasRows)
{
byte[] img = (byte[])(reader[0]);
if (img == null)
{
PicboxEmployee.Image = null;
}
else
{
MemoryStream mstrm = new MemoryStream(img);
PicboxEmployee.Image = new System.Drawing.Bitmap(mstrm); //there is error of parameter is not valid.
}
}
else
{
MessageBox.Show("this not exists");
}
推荐答案
不，那不行。
它似乎可以，但它没有做你有什么想法。
见这里：为什么我得到参数无效。我从数据库中读取图像时出现异常？ [ ^ ] - 解释问题和解决方案。
No, that won't work.
It may seem to, but it doesn't do what you think at all.
See here: Why do I get a "Parameter is not valid." exception when I read an image from my database?[^] - explains the problem and solution.
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