Pan*_*aNL 16 c# datagridview streamwriter
我正在开发一个应用程序,它将我的DataGridView名为scannerDataGridView导出到csv文件.
找到一些示例代码来执行此操作,但无法使其正常工作.顺便说一下,我的数据网格没有数据绑定到源.
当我尝试使用Streamwriter只编写列标题时一切顺利,但当我尝试导出整个数据网格包括数据时,我得到一个exeption trhown.
System.NullReferenceException:未将对象引用设置为对象的实例.在Scanmonitor.Form1.button1_Click(Object sender,EventArgs e)
这是我的代码,错误在以下行中给出:
dataFromGrid = dataFromGrid +','+ dataRowObject.Cells [i] .Value.ToString();
//csvFileWriter = StreamWriter
//scannerDataGridView = DataGridView
private void button1_Click(object sender, EventArgs e)
{
string CsvFpath = @"C:\scanner\CSV-EXPORT.csv";
try
{
System.IO.StreamWriter csvFileWriter = new StreamWriter(CsvFpath, false);
string columnHeaderText = "";
int countColumn = scannerDataGridView.ColumnCount - 1;
if (countColumn >= 0)
{
columnHeaderText = scannerDataGridView.Columns[0].HeaderText;
}
for (int i = 1; i <= countColumn; i++)
{
columnHeaderText = columnHeaderText + ',' + scannerDataGridView.Columns[i].HeaderText;
}
csvFileWriter.WriteLine(columnHeaderText);
foreach (DataGridViewRow dataRowObject in scannerDataGridView.Rows)
{
if (!dataRowObject.IsNewRow)
{
string dataFromGrid = "";
dataFromGrid = dataRowObject.Cells[0].Value.ToString();
for (int i = 1; i <= countColumn; i++)
{
dataFromGrid = dataFromGrid + ',' + dataRowObject.Cells[i].Value.ToString();
csvFileWriter.WriteLine(dataFromGrid);
}
}
}
csvFileWriter.Flush();
csvFileWriter.Close();
}
catch (Exception exceptionObject)
{
MessageBox.Show(exceptionObject.ToString());
}
Jon*_*han 32
LINQ FTW!
var sb = new StringBuilder();
var headers = dataGridView1.Columns.Cast<DataGridViewColumn>();
sb.AppendLine(string.Join(",", headers.Select(column => "\"" + column.HeaderText + "\"").ToArray()));
foreach (DataGridViewRow row in dataGridView1.Rows)
{
var cells = row.Cells.Cast<DataGridViewCell>();
sb.AppendLine(string.Join(",", cells.Select(cell => "\"" + cell.Value + "\"").ToArray()));
}
实际上,c.Value.ToString()将抛出null值,同时c.Value将正确转换为空字符串.
Ada*_*ite 18
一个鲜为人知的特性DataGridView是能够以编程方式选择部分或全部DataGridCell,并DataObject使用该方法将它们发送给a DataGridView.GetClipboardContent().这有什么好处呢？
A DataObject不仅存储对象,而且存储各种不同格式的对象.这就是剪贴板能够发挥其魔力的方式; 它存储了各种格式,不同的控件/类可以指定它们希望接受的格式.在这种情况下,DataGridView会将选定的单元格作为制表符分隔的文本格式,CSV格式或HTML(*)存储在DataObject中.
可以通过调用DataObject.GetData()或DataObject.GetText()方法并指定预定义的数据格式枚举来检索DataObject的内容.在这种情况下,我们希望CSV的格式为TextDataFormat.CommaSeparatedValue,然后我们可以使用System.IO.File类将该结果写入文件.
(*)实际上,它返回的内容严格来说不是HTML.此格式还包含您不期望的数据标头.虽然标题确实包含HTML的起始位置,但我只是丢弃HTML标记之上的任何内容myString.Substring(IndexOf("<HTML>"));.
请注意以下代码:
void SaveDataGridViewToCSV(string filename)
{
// Choose whether to write header. Use EnableWithoutHeaderText instead to omit header.
dataGridView1.ClipboardCopyMode = DataGridViewClipboardCopyMode.EnableAlwaysIncludeHeaderText;
// Select all the cells
dataGridView1.SelectAll();
// Copy selected cells to DataObject
DataObject dataObject = dataGridView1.GetClipboardContent();
// Get the text of the DataObject, and serialize it to a file
File.WriteAllText(filename, dataObject.GetText(TextDataFormat.CommaSeparatedValue));
}
现在,不是更好吗？为什么重新发明轮子？
希望这可以帮助...
我知道这可能已经死了但是我做了一个简单的代码,它根据DataGridView对象创建一个CSV并询问你想要保存它的位置.
它很直接,只需粘贴功能并使用它.它已经有一些基本的异常处理,所以使用起来非常安全.请享用.
private void SaveToCSV(DataGridView DGV)
{
string filename = "";
SaveFileDialog sfd = new SaveFileDialog();
sfd.Filter = "CSV (*.csv)|*.csv";
sfd.FileName = "Output.csv";
if (sfd.ShowDialog() == DialogResult.OK)
{
MessageBox.Show("Data will be exported and you will be notified when it is ready.");
if (File.Exists(filename))
{
try
{
File.Delete(filename);
}
catch (IOException ex)
{
MessageBox.Show("It wasn't possible to write the data to the disk." + ex.Message);
}
}
int columnCount = DGV.ColumnCount;
string columnNames = "";
string[] output = new string[DGV.RowCount + 1];
for (int i = 0; i < columnCount; i++)
{
columnNames += DGV.Columns[i].Name.ToString() + ",";
}
output[0] += columnNames;
for (int i = 1; (i - 1) < DGV.RowCount; i++)
{
for (int j = 0; j < columnCount; j++)
{
output[i] += DGV.Rows[i - 1].Cells[j].Value.ToString() + ",";
}
}
System.IO.File.WriteAllLines(sfd.FileName, output, System.Text.Encoding.UTF8);
MessageBox.Show("Your file was generated and its ready for use.");
}
}
编辑:改变了';' 到','因为我们在讨论CSV文件