C#

// assume you're inside a loop of some kind creating the ComboBoxes

cmbx = new ComboBox();
cmbx.SelectedIndexChanged += CmBoxIndexChanged;

// outside the loop
 
// In the EventHandler, get which ComboBox called it, and take action:

private void CmBoxIndexChanged(object sender, EventArgs e)
{
    // probably unnecessary; an example of "defensive" programming
    if (sender == null) throw new ArgumentNullException("Error in ComboBox SelectedIndexChanged");
    
    ComboBox caller = sender as ComboBox;
    
    switch (caller.Name)
    {
        case "ComboBox0":
            // take action for this ComboBox 
            break;
    
        case "ComboBox1":
            // take action for this ComboBox 
            break;

        // and so on ...
    }
}

foreach (ComboBox cBox in panel1.Controls)
{
    cBox.SelectedIndexChanged += cBox_SelectedIndexChanged;
}

void cBox_SelectedIndexChanged(object sender, EventArgs e)
{
    var currentComboBox = sender as ComboBox;

    if (currentComboBox == null)
          return;

    MessageBox.Show(currentComboBox.SelectedItem.ToString());
}

public void AddComboBox(ComboBox cBox, Action<int> callback)
{
// your implementation ...

// and a callback taking the index value or executing an update function
cBox.SelectedIndexChanged += (s,e) => { callback(cBox.SelectedIndex); };
}

The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections.

Member 12016106 wrote:

byte[] fileBytes = System.IO.File.ReadAllBytes(Files);

• Use the Response.TransmitFile method[^];
• Use the Response.WriteFile method[^];
• Read the file one block at a time and write each block to the response before reading the next block;

string physicalPath = ListBox1.SelectedValue;
if (!string.IsNullOrWhiteSpace(physicalPath))
{
    FileInfo fileToSend = new FileInfo(fileToSend);
    if (fileToSend.Exists)
    {
        System.Web.HttpContext context = System.Web.HttpContext.Current;
        context.Response.Clear();
        context.Response.ClearHeaders();
        context.Response.ClearContent();
        context.Response.ContentType = "application/octet-stream";
        context.Response.AddHeader("content-length", fileToSend.Length.ToString());
        context.Response.AppendHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlPathEncode(fileToSend.Name));
        context.Response.TransmitFile(fileToSend.FullName);
        context.Response.Flush();
        context.ApplicationInstance.CompleteRequest();
    }
}

// (Same code as before, up to and including the "Content-Disposition" header)

int bytesRead;
byte[] buffer = new byte[10000];
using (Stream fileStream = fileToSend.OpenRead())
{
    while (context.Response.IsClientConnected && (bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
    {
        context.Response.OutputStream.Write(buffer, 0, bytesRead);
        context.Response.Flush();
    }
}

context.ApplicationInstance.CompleteRequest();

// static so that all instances of the Class/Form/whatever use the same counter
private static int ComboBoxCounter = 0;

private const string ComboBoxNameBase = "ComboBox";

// keep a List of references to new ComboBoxes created
public List<ComboBox> TheComboBoxes = new List<ComboBox>();

public ComboBox GetNewComboBox()
{
    ComboBox cmbx = new ComboBox {Name = string.Format("{0}{1}",ComboBoxNameBase, ComboBoxCounter++)};
    TheComboBoxes.Add(cmbx);
    return cmbx;
}

// sample usage
// panel1.Controls.Add(GetNewComboBox()); // ComboBox0 added to Panel
// panel1.Controls.Add(GetNewComboBox()); // ComboBox1 added to Panel

TextBox tbProd = (TextBox)pn.Controls.Find("txtProdName" + i, false).FirstOrDefault();

tbProd.Text = "Blah";

TextBox tbProd = (TextBox)pn.Controls.Find("txtProdName" + i, false).FirstOrDefault();

TextBox tbProd = ....

pn.Controls["txtProdName3"].Text = "hello";

public List<TextBox> ListOfTextBoxes = new List<TextBox>();

public void createTextBoxes(int howMany)
{
    TextBox txtProdName;
    TextBox txtProdDesc;

    for(int i = 0; i < howMany; i++)
    {
        txtProdName = new TextBox();
        txtProdDesc = new TextBox();

        ListOfTextBoxes.Add(txtProdName); // keep a reference !
        ListOfTextBoxes.Add(txtProdDesc);
        
        txtProdName.Name = "txtProdName " + i;
        pn.Controls.Add(txtProdName);

        txtProdDesc.Name = "txtProdDesc " + i;
        pn.Controls.Add(txtProdDesc);
    }
}

// sample uses in code:

ListOfTextBoxes[2].Text = "blah";

// or, take advantage of the string Key of a ControlCollection

pn.Controls["txtProdName3"].Text = "hello";

string tbContent1 = ListOfTextBoxes[0].Text;