String must be exactly one character long ошибка

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;

namespace Excel_app
{
    public partial class Form4 : Form
    {
        char delimiter;
        Boolean dataloaded = false;

        public Form4()
        {
            InitializeComponent();
        }

        private void btnBrowse_Click(object sender, EventArgs e)
        {
            openFileDialog1.InitialDirectory = «C:»;
            openFileDialog1.Filter = «CSV files(*.csv)|*.CSV»;
            openFileDialog1.FilterIndex = 2;
            openFileDialog1.ShowDialog();
            txtFileName.Text = openFileDialog1.FileName;
        }

        private void btnLoad_Click(object sender, EventArgs e)
        {
            string fileRow;
            string[] fileDataField;
            int count = 0;
            if (dataloaded == false)
            {
                try
                {
                   
delimiter = Convert.ToChar(txtdelimiter.Text); ——>System.FormatException
                }
                catch (Exception exObject)
                {
                    MessageBox.Show(exObject.ToString());
                    this.Close();
                }

                try
                {
                    if (File.Exists(txtFileName.Text))
                    {
                        StreamReader fileReader = new StreamReader(txtFileName.Text);
                        if (fileReader.Peek() != -1)
                        {
                            fileRow = fileReader.ReadLine();
                            fileDataField = fileRow.Split(delimiter);
                            count = fileDataField.Count();
                            count = count — 1;

                            for (int i = 0; i <= count; i++)
                            {
                                DataGridViewTextBoxColumn columnDataGridTextBox = new DataGridViewTextBoxColumn();
                                columnDataGridTextBox.Name = fileDataField[i];
                                columnDataGridTextBox.HeaderText = fileDataField[i];
                                columnDataGridTextBox.Width = 120;
                                dataGridView1.Columns.Add(columnDataGridTextBox);
                            }
                        }
                        else
                        {
                            MessageBox.Show(«File is Empty.»);
                        }

                        while (fileReader.Peek() != -1)
                        {
                            fileRow = fileReader.ReadLine();
                            fileDataField = fileRow.Split(delimiter);
                            dataGridView1.Rows.Add(fileDataField);
                        }
                        fileReader.Close();
                    }
                    else
                    {
                        MessageBox.Show(«No File Is Selected.»);
                    }

                    dataloaded = true;
                }
                catch (Exception ExObject)
                {
                    MessageBox.Show(ExObject.ToString());
                }
            }
            else
            {
                MessageBox.Show(«Clear DataGridView First.»);
            }
        }

        private void btnSave_Click(object sender, EventArgs e)
        {
            try
            {
                delimiter = Convert.ToChar(txtdelimiter.Text);
            }
            catch(Exception ExObject)
            {
                MessageBox.Show(ExObject.ToString());
                this.Close();
            }

            try
            {
                StreamWriter fileWriter = new StreamWriter(txtFileName.Text, false);
                string columnHeaderText = «»;

                int countColumn = dataGridView1.ColumnCount — 1;

                if (countColumn >= 0)
                {
                    columnHeaderText = dataGridView1.Columns[0].HeaderText;
                }

                for (int i = 1; i <= countColumn; i++)
                {
                    columnHeaderText = columnHeaderText + delimiter + dataGridView1.Columns[i].HeaderText;
                }

                fileWriter.WriteLine(columnHeaderText);

                foreach (DataGridViewRow dataRowObject in dataGridView1.Rows)
                {
                    if (!dataRowObject.IsNewRow)
                    {
                        string dataFromGrid = «»;
                        dataFromGrid = dataRowObject.Cells[0].Value.ToString();

                        for (int i = 1; i <= countColumn; i++)
                        {
                            dataFromGrid = dataFromGrid + delimiter + dataRowObject.Cells[i].Value.ToString();
                        }

                        fileWriter.WriteLine(dataFromGrid);
                    }
                }

                MessageBox.Show(«Data Is Successfully saved in file.»);

                fileWriter.Flush();
                fileWriter.Close();
            }
            catch (Exception ExObject)
            {
                MessageBox.Show(ExObject.ToString());
            }
        }

        private void btnClear_Click(object sender, EventArgs e)
        {
            new Form4().Show();
            this.Dispose(false);
        }

       
    }
}

*An exception of type 'System.FormatException' occurred in mscorlib.dll but was not handled in user code
String must be exactly one character long.*

      string directions = Microsoft.VisualBasic.Interaction.InputBox("1 = Buy, 2 = Sell", "Select side", "Default", 700, 400);

      char direction = System.Convert.ToChar(directions);

2 ответа

Лучший ответ

char direction;

string directions = Microsoft.VisualBasic.Interaction.InputBox("1 = Buy, 2 = Sell", "Select side", "Default", 700, 400);

if(!string.IsNullOrEmpty(directions) && directions.Trim().Length == 1)
  direction = System.Convert.ToChar(directions);
else {
  direction = directions.FirstOrDefault(); // if thats what your logic
}

char direction = directions.FirstOrDefault();

If directions <> "1" And directions <> "2" Then
    'display error message to user
Else
    char direction = System.Convert.ToChar(directions);
    'proceed with your business logic
End If

char.Parse("<br />")

will give you a FormatException as char.Parse expects a string with a length of exactly 1 as the error message tells you.

You want to simply use string.Split(string)

var outPutArray = ieoutput.Split("<br />");

or for multiple separator options e.g. string.Split(string[])

var outPutArray = ieoutput.Split(new []{"<br />", "<br>", "<br/>"});

since most commonly the <br> tag is actually used without the closing /.

Since in general there are multiple ways how to exactly write these HTML tags in order to match all the different ways to write this you could also rather use Regex.Split like e.g.

var outPutArray = Regex.Split(ieoutput, "<br.*?>", RegexOptions.IgnoreCase | RegexOptions.SingleLine);

Here you match anything that

• Begins with <br (or <BR, <Br etc)
• Ends with the next >

not matter what comes between these, even if it is line breaks (see RegexOptions.SingleLine

See Regex Example and further Explanation on regex101.com

However as was already suggested, if you can change the output format actually the simplest solution of all would be rather use line breaks (n). It is a single character so you can simply use

var outPutArray = ieoutput.Split('n');