StreamWriter不会创建文本文件

Question

I have writtten a code to Create & write a file.But It doen't create a file.There's no any compilation error.My folder hierachy is DesktopModules -> SMSFunction->SMSText.I need to create a text file inside the SMSText folder,

public void WriteToFile(  string source, int dest, string messageIn, string operatorNew)
{
    try{

    string directory = ResolveUrl("~/DesktopModules/SMSFunction/SMSText");
    //string directory = Server.MapPath("~/DesktopModules/SMSFunction/SMSText");
    string filename = String.Format("{0:yyyy-MM-dd}__{1}.txt", DateTime.Now);
    string path = Path.Combine(directory, filename);

    if (!File.Exists(filename))
    {

        using (StreamWriter str = File.CreateText(path))
        {
            str.WriteLine("msisdn: " + source);
            str.WriteLine("shortcode : " + dest);
            str.WriteLine("Message : " + messageIn);
            str.WriteLine("Operator :" + operatorNew);
            str.Flush();

        }
    }
    else if (File.Exists(filename))
    {

        using (var str = new StreamWriter(filename))

        {
            str.WriteLine("msisdn: " + source);
            str.WriteLine("shortcode : " + dest);
            str.WriteLine("Message : " + messageIn);
            str.WriteLine("Operator :" + operatorNew);
            str.Flush();
        }

    }

}
catch(Exception ex)
{
    Response.Write(ex.Message);
}


}

Answer 1

There is something wrong here:

string filename = String.Format("{0:yyyy-MM-dd}__{1}.txt", DateTime.Now); . 

You call string.Format passing a format string that requires two parameters {0:yyyy-MM-dd} and {1} , but you give only one DateTime.Now . When your code reaches that line raises a FormatException and jumps to the catch block exiting without writing anything to disk.

EDIT: If you don't want to overwrite the contents of the file then you should use the overloaded constructor of StreamWriter that allows to Append to the existing file

.....
else if (File.Exists(filename))  
{  
    using (var str = new StreamWriter(filename, true))  
    {
         ....

but I think that you don't need that check on File.Exists. If you look carefully to the StreamWriter documentation you will see that the file is created when it doesn't exist. So the above code could really simplified to

    using (var str = new StreamWriter(path, true))      
    {      
        str.WriteLine("msisdn: " + source);      
        str.WriteLine("shortcode : " + dest);      
        str.WriteLine("Message : " + messageIn);      
        str.WriteLine("Operator :" + operatorNew);      
        str.Flush();      
    }     

removing the unnecessary if blocks

Answer 2

    private void SetPartnerTemplate()
        {
            var sb = new StringBuilder();
            widget.RenderControl(new HtmlTextWriter(new StringWriter(sb)));

            string setting = sb.ToString();

            string fileLoc = @"D:\sample1.txt";
            FileStream fs = null;
            if (!File.Exists(fileLoc))
            {
                using (fs = File.Create(fileLoc))
                {
                }
            }

            if (File.Exists(fileLoc))
            {
                using (StreamWriter sw = new StreamWriter(fileLoc))
                {
                    sw.Write(setting);
                }
            }
            if (File.Exists(fileLoc))
            {
                setting = File.ReadAllText(fileLoc);
            }
            else
            {
                Response.Write("<script language='javascript'>window.alert('File not found');</script>");
            }
            //after writing storing dat file to db

            //VoCServiceObj.SpSetWidgetRatingPartnerTemplate(setting, partnerid, productid);
        }

Answer 3

       protected void btnUpload_Click(object sender, EventArgs e)
           {
            var sb = new StringBuilder();
            widget.RenderControl(new HtmlTextWriter(new StringWriter(sb)));
            string setting = sb.ToString();
            string fileLoc = @"D:\Newsample.txt";
            FileStream fs = null;
            if (!File.Exists(fileLoc))
            {
                using (fs = File.Create(fileLoc))
                {
                }
            }
            if (File.Exists(fileLoc))
            {
                using (StreamWriter sw = new StreamWriter(fileLoc))
                {
                    sw.Write(setting);
                }
            }
            if (File.Exists(fileLoc))
            {
                setting = File.ReadAllText(fileLoc);
            }
            else
            {
                Response.Write("<script language='javascript'>window.alert('File not found');</script>");
            }

            FileStream st = new FileStream(fileLoc, FileMode.Open);
            byte[] buffer = new byte[st.Length];
            st.Read(buffer, 0, (int)st.Length);

            SqlConnection conn = new SqlConnection("Data Source=dsname;Initial Catalog=test;User ID=test;pwd=password");
            SqlCommand cmd1 = new SqlCommand();
            cmd1.Connection = conn;
            //OpenConnection(conn);
            conn.Open();
            SqlCommand cmd = new SqlCommand("INSERT INTO Files(Data) VALUES(@Data)", conn);


            //string commandText = "INSERT INTO Files VALUES(@Name, @ContentType, ";commandText = commandText + "@Size, @Data)";
            //cmd.CommandText = commandText;
            //cmd.CommandType = CommandType.Text;

            //cmd.Parameters.Add("@Name", SqlDbType.NVarChar, 100);
            //cmd.Parameters.Add("@ContentType", SqlDbType.VarChar, 50);
            //cmd.Parameters.Add("@size", SqlDbType.Int);
            cmd.Parameters.Add("@Data", SqlDbType.VarBinary);

            //cmd.Parameters["@Name"].Value = "name";
            //cmd.Parameters["@ContentType"].Value = "contentType";
            //cmd.Parameters["@size"].Value = 5;
            cmd.Parameters["@Data"].Value = buffer;
            cmd.ExecuteNonQuery();

            SqlCommand command = new SqlCommand("select Data from Files", conn);
            byte[] buffer3 = (byte[])command.ExecuteScalar();

            FileStream fs2 = new FileStream(@"D:\op.txt", FileMode.Create);
            fs2.Write(buffer, 0, buffer.Length);
            fs2.Close();
            st.Close();
            conn.Close();
        }