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1.
How to I introduce culture information into formatted strings?
2. How do I convert a string to an double or int?
3. How can I convert the string "Red" into the color Color.Red, and vice versa?
4. Is there a .Net way of deciding whether a string is numeric
or not?
5. How can I determine if a string is a valid date?
6. How can I convert an Enumeration member to string and
vice-versa?
7. My program dynamically builds lots of strings. Is there a
way to optimize string performance?
8. I hate string processing. Is there an easier way to do
string manipulation?
9. How do I use the CSV clipboard format supported by Excel?
10. Is there a easy way to test Regular Expressions?
1 How to I introduce culture information into formatted
strings?
You use the CultureInfo class found in the System.Globalization namespace.
DateTime dt = DateTime.Now;
textBox2.Text = dt.ToString("D", new CultureInfo("de-DE"));
textBox3.Text = dt.ToString("D", new CultureInfo("fr-FR"));
2 How do I convert a string to an double or int?
One way is to use static members of the Convert class in the System
namespace.
textBoxResult.Text =
Convert.ToString(Convert.ToDouble(textBox1.Text) *
Convert.ToDouble(textBox2.Text));
3 How can I convert the string "Red" into the color
Color.Red, and vice versa?
You can use the TypeDescriptor class to handle this.
Color redColor = (Color)TypeDescriptor.GetConverter(typeof(Color)).ConvertFromString("Red");
string redString =
TypeDescriptor.GetConverter(typeof(Color)).ConvertToString(Color.Red);
You can also use code such as
System.Drawing.ColorConverter
ccv = new System.Drawing.ColorConverter();
this.BackColor = (Color) ccv.ConvertFromString("Red");
4 Is there a .Net way of deciding whether a string is
numeric or not?
VB.NET has a IsNumeric method that you can use to recognize a Short,
Integer, Long, Decimal or Single numeric type. From C#, you can use
try/catch to look for a particular numeric type.
//long for a Single
Single num;
try
{
num = Single.Parse(someString);
}
catch (Exception e)
{
// if this is hit, someString is not a Single
}
5 How can I determine if a string is a valid date?
You can use the static DateTime.Parse or DateTime.ParseExact and catch any
exceptions.
System.DateTime myDateTime;
bool isValid = true;
try
{
myDateTime = System.DateTime.Parse(strMyDateTime);
}
catch (Exception e)
{
isValid = false;
}
6 How can I convert an Enumeration member to string and
vice-versa?
To convert an enum to string, do this:
string enumEntryAsString =
Enum.GetName(typeof(TabSizeMode), TabSizeMode.FillToRight);
To convert a string to an enum type:
// Enclose this code within
try/catch.
TabSizeMode sizeMode = Enum.Parse(typeof(TabSizeMode), "1");
(or)
TabSizeMode sizeMode =
Enum.Parse(typeof(TabSizeMode), "FillToRight");
7 My program dynamically builds lots of strings. Is
there a way to optimize string performance?
Use the StringBuilder class to concatenate strings. This class reuses
memory. If you add string members to concatenate them, there is extra
overhead as new memory is allocated for the new string. If you do a series
of concatenations using the strings (instead of StringBuilder objects) in a
loop, you continually get new strings allocated. StringBuilder objects
allocate a buffer, and reuse this buffer in its work, only allocating new
space when the initial buffer is consumed. Here is a typical use case.
StreamReader sr =
File.OpenText(dlg.FileName);
string s = sr.ReadLine();
StringBuilder sb = new StringBuilder();
while (s != null)
{
sb.Append(s);
s = sr.ReadLine();
}
sr.Close();
textBox1.Text = sb.ToString();
8 I hate string processing. Is there an easier way to do
string manipulation?
.NET has excellent support for Regular Expressions. Get the excellent
"Regular Expressions with .NET ", e-book by Dan Appleman. It has all that
you need to get started.
Regular expressions really make string processing easier.
There are expressions that you can find on the web for everything from
validating dates to phone numbers. There are several available at this site:
http://regxlib.com/
9 How do I use the CSV clipboard format supported by
Excel?
In this case, the dataobject is a memory stream. Here are code snippets that
allow you to get/set CSV values from/to the clipboard in a manner compatible
with Excel.
[C#]
private void GetCSVFromClipBoard_Click(object sender, System.EventArgs e)
{
IDataObject o = Clipboard.GetDataObject();
if(o.GetDataPresent(DataFormats.CommaSeparatedValue))
{
StreamReader sr = new StreamReader((Stream)
o.GetData(DataFormats.CommaSeparatedValue));
string s = sr.ReadToEnd();
sr.Close();
Console.WriteLine(s);
}
}
private void CopyCSVToClipBoard_Click(object sender, System.EventArgs e)
{
String csv = "1,2,3" + Environment.NewLine + "6,8,3";
byte[] blob = System.Text.Encoding.UTF8.GetBytes(csv);
MemoryStream s = new MemoryStream(blob);
DataObject data = new DataObject();
data.SetData(DataFormats.CommaSeparatedValue, s);
Clipboard.SetDataObject(data, true);
}
[VB.NET]
Private Sub GetCSVFromClipBoard_Click(ByVal sender As System.Object, ByVal e
As System.EventArgs) Handles Button1.Click
Dim o As IDataObject = Clipboard.GetDataObject()
If Not o Is Nothing Then
If (o.GetDataPresent(DataFormats.CommaSeparatedValue)) Then
Dim sr As New
StreamReader(CType(o.GetData(DataFormats.CommaSeparatedValue), Stream))
Dim s As String = sr.ReadToEnd()
sr.Close()
Console.WriteLine(s)
End If
End If
End Sub 'GetCSVFromClipBoard_Click
Private Sub CopyCSVToClipBoard_Click(ByVal sender As System.Object, ByVal e
As System.EventArgs) Handles Button2.Click
Dim csv As String = "1,2,3" + Environment.NewLine + "6,8,3"
Dim blob As Byte() = System.Text.Encoding.UTF8.GetBytes(csv)
Dim s As New MemoryStream(blob)
Dim data As New DataObject()
data.SetData(DataFormats.CommaSeparatedValue, s)
Clipboard.SetDataObject(data, True)
End Sub 'CopyCSVToClipBoard_Click
10 Is there a easy way to test Regular Expressions?
There are several tools that allow you to quickly test your regular
expressions. Listed below are two that we use:
Expresso on
CodeProject
RegexDesigner on
SellsBrothers.com
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