C#QuotedStr方法实现,引号的处理

protected string QuotedStr(string S)
{
string vResult;
vResult = S;
for (int i = vResult.Length-1; i >= 0; i--)
{
if (vResult[i].Equals('\''))
{
vResult=vResult.Insert(i, "\'");
}
}
vResult = "'" + vResult + "'";
return vResult;
}

private void button1_Click(object sender, EventArgs e)
{
string vString,vTemp,vCondition;
vString = "ab'cd";
vCondition = string.Format("ProjectName= {0}", QuotedStr(vString));
MessageBox.Show(vCondition);
}