C# 字符串截取（包括汉字）

private void GetSubString()
{

//截取的长度
int count = 0;
if (!string.IsNullOrEmpty(txtCount.Text))
{
count = Convert.ToInt32(txtCount.Text);
}

if (count >= 2)
{

//将截取的内容转化为byte
byte[] content = System.Text.Encoding.Default.GetBytes(txtContent.Text);

//将截取后的内容放到临时数组中

byte[] temp = new byte[] { content[count - 1] };

//将截取后的内容转化为字符串

string strTemp = System.Text.Encoding.Default.GetString(temp);

//判断字符串截取是否正确
if (!txtContent.Text.Contains(strTemp))
{
temp = new byte[] { content[count - 2], content[count - 1] };
strTemp = System.Text.Encoding.Default.GetString(temp);
if (!txtContent.Text.Contains(strTemp))
{
count++;
}
}

byte[] showContent = new byte[count];
for (int i = 0; i < count; i++)
{
showContent[i] = content[i];
}

lblShow.Text = System.Text.Encoding.Default.GetString(showContent);
lblCount.Text = count.ToString();
}
else
{
lblShow.Text = txtContent.Text.Substring(0, count);
lblCount.Text = count.ToString();
}
}