c#学习笔记（二）：保存图片、保存DataGridView数据到本地和从本地读取到DataGridView

private void saveBtn_Click(object sender, System.EventArgs e)
{
bool isSave = true;
SaveFileDialog saveImageDialog = new SaveFileDialog();
saveImageDialog.Title = "图片保存";
saveImageDialog.Filter= @"jpeg|*.jpg|bmp|*.bmp|gif|*.gif";

if(saveImageDialog.ShowDialog() == DialogResult.OK)
{
string fileName = saveImageDialog.FileName.ToString();

if(fileName != "" && fileName != null)
{
string fileExtName = fileName.Substring(fileName.LastIndexOf(".")+1).ToString();

System.Drawing.Imaging.ImageFormat imgformat = null;

if(fileExtName!="")
{
switch(fileExtName)
{
case "jpg":
imgformat = System.Drawing.Imaging.ImageFormat.Jpeg;
break;
case "bmp":
imgformat = System.Drawing.Imaging.ImageFormat.Bmp;
break;
case "gif":
imgformat = System.Drawing.Imaging.ImageFormat.Gif;
break;
default:
MessageBox.Show("只能存取为: jpg,bmp,gif 格式");
isSave = false;
break;
}

}

//默认保存为JPG格式
if(imgformat == null)
{
imgformat = System.Drawing.Imaging.ImageFormat.Jpeg;
}

if(isSave)
{
try
{

<span style="white-space:pre">			</span>//此处等等picture_QRCode是图片控件的name
this.picture_QRCode.Image.Save(fileName, imgformat);
//MessageBox.Show("图片已经成功保存!");
}
catch
{
MessageBox.Show("保存失败,你还没有截取过图片或已经清空图片!");
}
}

}

}
}

private void saveData_Click(object sender, EventArgs e)
{
//实例化一个保存文件对话框
SaveFileDialog sf = new SaveFileDialog();
//设置文件保存类型
sf.Filter = "txt文件|*.txt";
//如果用户没有输入扩展名，自动追加后缀
sf.AddExtension = true;
//设置标题
sf.Title = "写文件";
//如果用户点击了保存按钮
if (sf.ShowDialog() == DialogResult.OK)
{
//实例化一个文件流--->与写入文件相关联
FileStream fs = new FileStream(sf.FileName, FileMode.Create);
//实例化一个StreamWriter-->与fs相关联
StreamWriter sw = new StreamWriter(fs);
//开始写入
if (this.dataGridView1.Rows.Count < 1)
{
MessageBox.Show("没有数据！导出失败！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);

}
else
{
//因为DataGridView最后一行为空，所以减一
sw.WriteLine(this.dataGridView1.Rows.Count-1);
for (int i = 0; i < this.dataGridView1.Rows.Count-1; i++)
{
//如果某一列数据为空，就写入""，因为空对象不能调用tostring()；
if (this.dataGridView1.Rows[i].Cells[0].Value != null)
sw.WriteLine(this.dataGridView1.Rows[i].Cells[0].Value.ToString());
else
sw.WriteLine("");
if (this.dataGridView1.Rows[i].Cells[1].Value != null)
sw.WriteLine(this.dataGridView1.Rows[i].Cells[1].Value.ToString());
else
sw.WriteLine("");
if (this.dataGridView1.Rows[i].Cells[2].Value != null)
sw.WriteLine(this.dataGridView1.Rows[i].Cells[2].Value.ToString());
else
sw.WriteLine("");
if (this.dataGridView1.Rows[i].Cells[3].Value != null)
sw.WriteLine(this.dataGridView1.Rows[i].Cells[3].Value.ToString());
else
sw.WriteLine("");
if (this.dataGridView1.Rows[i].Cells[4].Value != null)
sw.WriteLine(this.dataGridView1.Rows[i].Cells[4].Value.ToString());
else
sw.WriteLine("");
if (this.dataGridView1.Rows[i].Cells[5].Value != null)
sw.WriteLine(this.dataGridView1.Rows[i].Cells[5].Value.ToString());
else
sw.WriteLine("");
if (this.dataGridView1.Rows[i].Cells[6].Value != null)
sw.WriteLine(this.dataGridView1.Rows[i].Cells[6].Value.ToString());
else
sw.WriteLine("");
if (this.dataGridView1.Rows[i].Cells[7].Value != null)
sw.WriteLine(this.dataGridView1.Rows[i].Cells[7].Value.ToString());
else
sw.WriteLine("");
if (this.dataGridView1.Rows[i].Cells[8].Value != null)
sw.WriteLine(this.dataGridView1.Rows[i].Cells[8].Value.ToString());
else
sw.WriteLine("");
}
//写入性别
sw.WriteLine(sex);
sw.WriteLine(age);
sw.WriteLine(season);
sw.WriteLine(CatCode);
//写入商品价格
sw.WriteLine(textBox_goodPrice.Text);
sw.WriteLine(textBox_goodSaleVolume.Text);
sw.WriteLine(textBox_goodName.Text);
sw.WriteLine(textBox_goodTag.Text);
sw.WriteLine(textBox_goodLink.Text);
sw.WriteLine(textBox_goodPicLink.Text);

//清空缓冲区
sw.Flush();
//关闭流
sw.Close();
fs.Close();
MessageBox.Show("保存成功！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
}

//加载本地数据到表格
private void loadData_Click(object sender, EventArgs e)
{

//实例化一个保存文件对话框
OpenFileDialog sf = new OpenFileDialog();
//设置文件保存类型
sf.Filter = "txt文件|*.txt";
//如果用户没有输入扩展名，自动追加后缀
sf.AddExtension = true;
//设置标题
sf.Title = "读文件";
//如果用户点击了保存按钮
if (sf.ShowDialog() == DialogResult.OK)
{
//实例化一个文件流--->与写入文件相关联
FileStream fs = new FileStream(sf.FileName, FileMode.Open);
//实例化一个StreamWriter-->与fs相关联
StreamReader sw = new StreamReader(fs);
//开始读取
if (this.dataGridView1.Rows.Count < 1)
{
MessageBox.Show("没有数据！读取失败！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);

}
else
{
int RowCount = int.Parse(sw.ReadLine());
//判断如果大于读取的行数小于等于当前dataGridView的行数，就不add行，否则add行
if (RowCount < this.dataGridView1.Rows.Count || RowCount == this.dataGridView1.Rows.Count)
{
for (int i = 0; i < RowCount; i++)
{
this.dataGridView1.Rows[i].Cells[0].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[1].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[2].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[3].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[4].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[5].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[6].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[7].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[8].Value = sw.ReadLine();
}
}
else
{
for (int i = 0; i < RowCount; i++)
{
this.dataGridView1.Rows.Add();
this.dataGridView1.Rows[i].Cells[0].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[1].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[2].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[3].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[4].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[5].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[6].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[7].Value = sw.ReadLine();
this.dataGridView1.Rows[i].Cells[8].Value = sw.ReadLine();
}
}
//读取性别Sex
string sexRead = sw.ReadLine();
switch(sexRead)
{
case "1":
radioSex_m.Checked=true;
break;
case "2":
radioSex_f.Checked=true;
break;
case "0":
radioSex_n.Checked=true;
break;
}
//读取年龄
string ageRead = sw.ReadLine();
switch(ageRead)
{
case "1":
radioAge_1.Checked=true;
break;
case "2":
radioAge_2.Checked=true;
break;
case "3":
radioAge_3.Checked=true;
break;
}
//读取季节
string seasonRead = sw.ReadLine();
switch(seasonRead)
{
case "1":
radioSeason_s.Checked=true;
break;
case "2":
radioSeason_w.Checked=true;
break;
case "3":
radioSeason_a.Checked=true;
break;
}
//读取分类
string CatCodeRead = sw.ReadLine();
switch(CatCodeRead)
{
case "1":
radioCat_1.Checked=true;
break;
case "2":
radioCat_2.Checked=true;
break;
case "11":
radioCat_11.Checked=true;
break;
case "12":
radioCat_12.Checked=true;
break;
case "13":
radioCat_13.Checked=true;
break;
case "14":
radioCat_14.Checked=true;
break;
}
//读取商品价格
textBox_goodPrice.Text = sw.ReadLine();
//读取商品销量
textBox_goodSaleVolume.Text = sw.ReadLine();
//读取商品名称
textBox_goodName.Text = sw.ReadLine();
//读取商品标签
textBox_goodTag.Text = sw.ReadLine();
//读取商品链接
textBox_goodLink.Text = sw.ReadLine();
//读取图片链接
textBox_goodPicLink.Text = sw.ReadLine();

//sw.Write(this.textBox1.Text);
//清空缓冲区
//  sw.Flush();
//关闭流
sw.Close();
fs.Close();
MessageBox.Show("读取成功！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
}
}