将Byte []转换为图像并在asp.net中显示 [英] Convert Byte[] to image and show in asp.net

问题描述

我已经以字节形式在SQL SERVER中保存我的图像，我想在asp.net c＃中的标签上显示它。

我已经尝试了很多但无法做到。

我是初学者。

所以请建议

解决方案

使用类 System.IO.MemoryStream ：使用 byte [] 数据构造此类的实例作为构造函数参数，然后从该字符串中读取图像：

http://msdn.microsoft.com /en-us/library/system.io.memorystream%28v=vs.110%29.aspx [ ^ ]，

http://msdn.microsoft.com/en-us/library/e55f3s5k(v=vs.110).aspx [ ^ ]，

http://msdn.microsoft.com/en-us/library/93z9ee4x%28v=vs.110%29.aspx [ ^ ]。

-SA

hi。我只用于每个..我发布了完整的编码。你可以看看有什么问题



private void bindingroodrecord（）



{



sql =EXEC [sp_parent_record]; //存储过程以获取父记录



SqlCommand cmd = new SqlCommand（sql，objConn）;

SqlDataAdapter da = new SqlDataAdapter（cmd ）;

DataTable dt1 = new DataTable（）;

da.Fill（dt1）;

Session [parentnode] = dt1;



PopulateNodes（dt1，TreeView1.Nodes）; /////////为父节点



}



private void PopulateNodes（DataTable） dt，TreeNodeCollection节点）

{

foreach（dt.Rows中的DataRow dr）

{

TreeNode tn = new TreeNode（）;



tn.Text = dr [columnfield]。ToString（）。Trim（）;



tn.Value = dr [code_webcategory_id]。ToString（）。Trim（）;

tn.ImageUrl = string.Format（image.aspx？category = { 0}&width = 50，tn.Value）;

nodes.Add（tn）;





tn.PopulateOnDemand =（Convert.ToInt32（dr [childnodecount]）> 0）;



}





}

以上编码工作正常。



注意：image.aspx， image来自数据库（以字节形式出现），然后使用System.Drawing.Image bitmap = System.Drawing.Image.FromStream（stream）写入图像，......图像来自数据库并以tn绑定。图像正确。



所以，现在因为我有100条记录它绑定图像100次没关系。



现在下面的代码绑定子注释



protected void TreeView1_TreeNodePopulate（object sender，TreeNodeEventArgs e）

{





PopulateSubLevel（Convert.ToInt32（e.Node.Value），e.Node）; //当用户在树视图上单击（填充）以形成父节点的子节点时，我将获得父节点。





} < br $>


private void PopulateSubLevel（int parentid，TreeNode parentNode）

{



SqlCommand cmd = new SqlCommand（sp_getchildrecords，objConn）; ///这是使用父ID获取子节点的存储过程。

cmd.CommandType = CommandType.StoredProcedure;

cmd.Parameters.Add（@ parentID，SqlDbType.Int）.Value = parentid;

SqlDataAdapter da = new SqlDataAdapter（cmd）;

DataTable dt = new DataTable（）;

da.Fill（dt）;

Session [childnode] = dt;

Session [childnodess ] = parentNode;

TreeNode childrecords =（TreeNode）Session [childnodess];



PopulateNodes（dt，childrecords.ChildNodes） ; //形成子节点





}

这也可行。但是，



现在，考虑子节点有10条记录。一旦populateNodes函数结束，它就会调用image.aspx来获取图像。现在它再次绑定110次而不是绑定10次。

参考此链接

http://stackoverflow.com/questions/20771432/bind-an-image-in-c-sharp-using-byte-array [ ^ ]

I have save my Image in SQL SERVER in byte form and i want to show it on label in asp.net c#.
I have tried alot but unable to do.
I m beginer.
So please suggest

解决方案

Use the class System.IO.MemoryStream: construct the instance of this class using your byte[] data as a constructor parameter and then read the image from this string:
http://msdn.microsoft.com/en-us/library/system.io.memorystream%28v=vs.110%29.aspx[^],
http://msdn.microsoft.com/en-us/library/e55f3s5k(v=vs.110).aspx[^],
http://msdn.microsoft.com/en-us/library/93z9ee4x%28v=vs.110%29.aspx[^].

—SA

hi. i used for each only.. i posted full coding. you can see what is the problem

private void bindingroodrecord()

{

sql = "EXEC [sp_parent_record]"; //stored procedur to get parent records

SqlCommand cmd = new SqlCommand(sql, objConn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt1 = new DataTable();
da.Fill(dt1);
Session["parentnode"] = dt1;

PopulateNodes(dt1, TreeView1.Nodes); ///////// for parent node

}

private void PopulateNodes(DataTable dt, TreeNodeCollection nodes)
{
foreach (DataRow dr in dt.Rows)
{
TreeNode tn = new TreeNode();

tn.Text = dr["columnfield"].ToString().Trim();

tn.Value = dr["code_webcategory_id"].ToString().Trim();
tn.ImageUrl = string.Format("image.aspx?category={0}&width=50", tn.Value);
nodes.Add(tn);


tn.PopulateOnDemand = (Convert.ToInt32(dr["childnodecount"]) > 0);

}


}
The above coding works fine.

NOTE: image.aspx, image comes from database(which comes as byte) and then writting as image using System.Drawing.Image bitmap = System.Drawing.Image.FromStream(stream),......the image comes from database and binds in tn.imageurl correctly.

so, right now as i have 100 records it binds image 100 time which is ok.

now the below coding to bind child notes

protected void TreeView1_TreeNodePopulate(object sender, TreeNodeEventArgs e)
{


PopulateSubLevel(Convert.ToInt32(e.Node.Value), e.Node); // i am getting parent node when user click (populate)on treeview to form a child node for parent node.


}

private void PopulateSubLevel(int parentid, TreeNode parentNode)
{

SqlCommand cmd = new SqlCommand("sp_getchildrecords", objConn);/// this is the stored procedure to get child node using parent id.
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add("@parentID", SqlDbType.Int).Value = parentid;
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
Session["childnode"] = dt;
Session["childnodess"] = parentNode;
TreeNode childrecords = (TreeNode)Session["childnodess"];

PopulateNodes(dt, childrecords.ChildNodes); // to form child nodes


}
this also works fine. but,

Now, consider the child node has 10 records. once the populateNodes function gets over , it calls image.aspx to get an image. Now it binds 110 time again instead of binding 10 times.

refer this link
http://stackoverflow.com/questions/20771432/bind-an-image-in-c-sharp-using-byte-array[^]

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