在vb.net中格式化字符串

Question

Is there anything like formatting a string to the format specified?

Eg:

If the string value is

"05/05/2013 05:06:23"

If the formatting type is

"d"

So if we pass both the values, the output should be

05/05/2013

I tried like using the function Format("stirng value","format") , but this gave me the format as o/p.

Note : The function should work for all the datatypes .

Answer 1

You'll have to parse it into a DateTime object and then use the ToString again with your specified format.

Dim str = "05/05/2013 05:06:23"
Dim ci = new CultureInfo("en-US")
Dim formattedDate = DateTime.Parse(str).ToString("dd/MM/yyyy", ci) // Returns 05/05/2013"

And no, there is no such thing which works for all data types.

If you want to convert another data type ( Decimal for example ), first convert your string into the respective type ( Decimal.Parse ..etc) and then use ToString again for the desired format.

Answer 2

You can create your own function like this ..

This function can accept any type and return any type (only tested on int and date)

Function ChangeThis(ByVal var As Object, ByVal Type As String) As Object
    If Not var.GetType.IsValueType() Then Return Nothing
    Select Case var.GetType().ToString
        Case "System.Int32" : MsgBox("Integer 32")
        Case "System.DateTime"
            If Type = "d" Then Return Convert.ToDateTime(var).Date
    End Select
    Return ""
End Function

You can test it

Dim s As Date = ChangeThis(Now(), "d")
MsgBox(s)

This is not too good, but it can help ..

Answer 3

The VB.NET Format function will give you what you want; you just have to read the documentation to ensure you supply known formats:

> (Strings:Format "12-03-04 5:01:23.456" "d")
d
> (Strings:Format "12-03-04 5:01:23.456" "Short Date")
12/03/2004
> (Strings:Format "12-03-04 5:01:23.456" "Long Date")
Friday, 12 March 2004
> (Strings:Format "50123.456" "Currency")
$50,123.46
>

_{The above is actually DotLisp and its output, but it is just calling Microsoft.VisualBasic.Strings.Format .}

Answer 4

为此，您必须首先将字符串解析为datetime，然后可以使用：

myDateVariable.ToString("d")

Answer 5

Try using the .net string.format function. Howver, the format string needs to specify exactly what output you want. Just using "format" as the format string will output "format", as you've already discovered.

Answer 6

尝试

Convert.ToDateTime("05/05/2013 05:06:23").ToString("dd/MM/yyyy")

Answer 7

Your can try this.

 Dim strRawdate As String = "05/05/2013 05:06:23"
 Dim dt As DateTime = DateTime.ParseExact(strRawdate, "M/d/yyyy HH:mm:ss", System.Globalization.CultureInfo.InvariantCulture)
 Dim reformatDate As String = dt.ToString("M/d/yyyy", System.Globalization.CultureInfo.InvariantCulture)