将按钮单击时定义的变量传递到另一个按钮单击c#

我正在编写一个ASP.NET应用程序，单击按钮即可执行以下操作

1. 使用GUID在App_Data文件夹中创建唯一目录
2. 将exe文件和excel模板复制到唯一目录中
3. 根据网页输入编写一个txt文件
4. 运行exe文件
5. exe生成一个输出txt文件
6. 将输出数据放入网页上的asp表中
7. 将txt文件中的输出数据写入excel模板

第二个按钮点击

1. 下载带有数据的唯一excel文件

现在所有涉及的路径都是变量。我想做的是点击第二个按钮，让你下载充满数据的独特excel文件。然而，无论我尝试什么，我都无法在第二次点击按钮时使用excel文件的唯一路径。

那么，我如何在第二次点击中传递第一次点击中定义的变量呢。重要的是，在第一次单击按钮时创建唯一的目录。

这是一些代码。有很多，所以我试图只张贴重要的东西

public void Button1_Click(object sender, EventArgs e)
{
    UniqueDirectory d = new UniqueDirectory();
    string dirPath = Request.MapPath("~/App_Data/");             // point to the directory of wispp on the server
    string wisppExe = Server.MapPath("~/App_Data/WisppNew.exe"); // point to the location of wispp on the server
    string fortranLib = Server.MapPath("~/App_Data/libf60rts.dll"); // point to the location of the fortran libray file on the server
    string excelTemplate = Server.MapPath("~/App_Data/WISPP_Template.xls");
    do
    {
        Guid guid = Guid.NewGuid();
        string uniqueSubFolderName = guid.ToString();
        string uniquePath = dirPath + uniqueSubFolderName;
    }
    while (Directory.Exists(d.uniquePath));
    Directory.CreateDirectory(d.uniquePath);
    //copy files to new unique directory
    string wisppUnique = Path.Combine(d.uniquePath, "WisppNew.exe");
    string fortranUnique = Path.Combine(d.uniquePath, "libf60rts.dll");
    string wisppGraphUnique = Path.Combine(d.uniquePath, "WISPPGRA");
    string excelUnique = Path.Combine(d.uniquePath, "WISPP_Template.xls");
    string excelOutput = Path.Combine(d.uniquePath, "WISPP_Output.xls");
    File.Copy(wisppExe, wisppUnique, true);
    File.Copy(fortranLib, fortranUnique, true);
    File.Copy(excelTemplate, excelUnique, true);
    //write data into excel        
    FileStream outputFile = new FileStream(excelOutput, FileMode.OpenOrCreate, FileAccess.Write);
    xssfworkbook.Write(outputFile);
    outputFile.Close();
}
public void Button2_Click(object sender, EventArgs e)
{
    //here I want to use variable excelOutput
    FileInfo file = new FileInfo(excelOutput);
    if(file.Exists)
    {
        Response.Clear();
        Response.ClearHeaders();
        Response.ClearContent();
        Response.AddHeader("Content-Disposition", "attachment; filename=" + file.Name);
        Response.AddHeader("Content-Length", file.Length.ToString());
        Response.ContentType = "Application/x-msexcel";
        Response.Flush();
        Response.TransmitFile(file.FullName);
        Response.End();
    }
}

希望这是有道理的。我曾尝试将代码的响应部分放在第一次单击按钮中，但由于某种原因，这使得数据表不可见。此外，我希望用户可以选择下载excel文件，所以我理想情况下需要第二次点击按钮。

//hide second button
yourButton2.Visible = false;
public void Button1_Click(object sender, EventArgs e)
{
    UniqueDirectory d = new UniqueDirectory();
    string dirPath = Request.MapPath("~/App_Data/");             // point to the directory of wispp on the server
    string wisppExe = Server.MapPath("~/App_Data/WisppNew.exe"); // point to the location of wispp on the server
    string fortranLib = Server.MapPath("~/App_Data/libf60rts.dll"); // point to the location of the fortran libray file on the server
    string excelTemplate = Server.MapPath("~/App_Data/WISPP_Template.xls");
    do
    {
        Guid guid = Guid.NewGuid();
        string uniqueSubFolderName = guid.ToString();
        string uniquePath = dirPath + uniqueSubFolderName;
    }
    while (Directory.Exists(d.uniquePath));
    Directory.CreateDirectory(d.uniquePath);
    //copy files to new unique directory
    string wisppUnique = Path.Combine(d.uniquePath, "WisppNew.exe");
    string fortranUnique = Path.Combine(d.uniquePath, "libf60rts.dll");
    string wisppGraphUnique = Path.Combine(d.uniquePath, "WISPPGRA");
    string excelUnique = Path.Combine(d.uniquePath, "WISPP_Template.xls");
    string excelOutput = Path.Combine(d.uniquePath, "WISPP_Output.xls");
    File.Copy(wisppExe, wisppUnique, true);
    File.Copy(fortranLib, fortranUnique, true);
    File.Copy(excelTemplate, excelUnique, true);
    //write data into excel        
    FileStream outputFile = new FileStream(excelOutput, FileMode.OpenOrCreate, FileAccess.Write);
    xssfworkbook.Write(outputFile);
    outputFile.Close();
    yourButton2.Visible = true;
    yourButton2.Click += (_sender, _e) =>
    {
        //excelOutput is still in scope
        FileInfo file = new FileInfo(excelOutput);
        if(file.Exists)
        {
            Response.Clear();
            Response.ClearHeaders();
            Response.ClearContent();
            Response.AddHeader("Content-Disposition", "attachment; filename=" + file.Name);
            Response.AddHeader("Content-Length", file.Length.ToString());
            Response.ContentType = "Application/x-msexcel";
            Response.Flush();
            Response.TransmitFile(file.FullName);
            Response.End();
        }
    };
}

    Session["excelPath"] = excelOutput;

    string excelOutput = (string)Session["excelPath"];