Possible Duplicate: C#: why does the string type have a .ToString() method?Why is there a ToString method exist in String class (VB.NET)?
String.ToString()
Will it be a overhead if it is used like
TextBox.Text.ToString()
I have nine pictures that I need to animate -I need to use the ToString method and a counter to concatenate a file name into a string variable from the Image.FromFile method. Once the counter reaches its maximum value, and the last picture is displayed, the counter should be reset to zero or one depending on how the first image file has been name. Also a static counter variable should be incremented in the time routine. what I have so far -- I know what I have to do; however, I just do not know how to code this properly.. Right now I have this going thru a button procedure but it needs to go through a timer.
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am trying to get the following code to work:
Dim testString As String
testString = cbbxStartDt.SelectedValue.ToString("yyyyMMdd")
when doing so the code is being stoped and I get "InvalidCastException" error emssage:
Conversion from string "yyyyMMdd" to type 'Integer' is not valid.
If I do the following, then it works:
Dim testDate As Date
Dim testString As String
testDate = cbbxStartDt.SelectedValue
testString = testDate.ToString("yyyyMMdd")
This, returns the desired value: "20110103"
NB:
cbbxStartDt.SelectedValue.ToString returns: "03/01/2011 00:00:00"
So would it be possible that the problem comes from of the "time bit" : "00:00:00"?if, so is it the parsetime function which would allow to take into account only the time bit value of the combobox?
In VB.NET, it is entirely possible to pass an integer as a string parameter to a method without calling .ToString() - it's even possible to call .ToString without the ()'s. The code will run without a problem, VB will interpret the integer as a string without having been told to. In C#, these would cause compilation errors - you are required to call .ToString() and to call it correctly in that situation before it will compile. Is there a way to make the VB compilation process check for the same things as the C# compilation process? Would it be best practice in a mixed team to force this check?
View 3 RepliesI am facing an amazing problem in my application. On my Developement server when I am running my application, then there is one function where I am trying to put whole stringbuilder contents in a string object. This Function is used for paging the reports.For that I am using a method of Stringbuilder.tostring() and when I chek the value of this statement (stringbuilder.tostring()) it shows no such interface is supported, which later on throws exception of system is out of memory. Here i am using .net 2.0 framework and sql server 2005 database.But when I run the application on stagging server then there is no such exception thrown.[code]
View 3 RepliesI am working in a form, and I had to this
Dim par1 as string = "something"
I want pass par1 to update sql statement, and I am not using AddParameter So, I had to add single quotes, the par1 will be
par1 = "'" + par1 + "'"
instead of doing the above, I was thinking in
par1 = par1.ToString.AddSingleQuote
or
par1 = par1.AddSingleQuote
Either to add "AddSingleQuote" to "ToString" method, or make it available for every variable of type "String" Can that be done?
Given a list of objects, I'd like to print a string version of them just in case the object.ToString() result is a relevant string.By that I mean I don't want to get things like:
obj.ToString() -> System.Collections.Generic.List`1[MyLib.Dude]
obj.ToString() -> System.Collections.Generic.Dictionary`2[System.Int32,System.DateTime]
obj.ToString() -> System.Byte[]
But I want to get things like:
obj.ToString() -> Hi
obj.ToString() -> 129847.123
obj.ToString() -> Id = 123
What should be the best way to implement this in a method:
Public Sub PrintInterestingStuffOnly(ByVal coolList as Ilist(Of Object))
For Each obj in coolList
'insert solution here
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I am using .net 2.0 and I am getting an exception of system is out of memory. My existing function takes datatable as input parameter which contains little bit large data (eg. more than 35000 rows) and in that function I am appending some xml node data and atlast I am returning the stringbuilder as a object.
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How would I override the method ToString() for the property CheckBox.Checked?
View 2 RepliesI just converted a VB.net solution into C# solution. But lots of variables have been coverted like:
string var1 = (string)1;
string var2 = (string)intVar; //intVar is a int value
I just want to convert all (string)XXXX to XXXX.ToString() by using some Regular expressions or some other replace methods.
I have a copy function that I'd like to override in subclasses to return the type of the subclass. Here are my interfaces:
Public Interface IBase(Of T)
Function Copy() As T
End Interface
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I've a simple class like this:
Public Class CalculationParameter{
public Long TariffId{get;set;}
}
In a workflow activity, I've an Assign like this:
(From tariffDetail In db.Context.TariffDetails
Where tariffDetial.TariffId = calculationParameter.TariffId).FirstOrDefault()
Dto is passed to Activity as an Input Argument.It raise following error and I'm wondering how to assign Id.LINQ to Entities does not recognize the method 'Int64
GetValue[Int64](System.Activities.LocationReference)' method, and this method cannot be translated into a store expression.
How can I assign the calculationParameter.TariffId to tariffDetial.TariffId?!
UPDATE:Screen shot attached shows that how I'm trying to assign calculationParameter.TariffId to tariffDetail.TariffId (car.Id = Dto.Id) and the query result should assign to CurrentTrafficDetail object.
1. What's the difference between ToString and ToString()? (i do know that ToString method is to cast numeric values to string but don't know how to get it to work)
2. Why do i need XML comment feature? is it necessary?
Let's say I have a page Test.aspx along with test.aspx.vb.Test.aspx.vb contains a class name "TestClass". In that class I have method1(), method2() and method3()I need to be able to call one of those methods, but I can't hard code it, the method to be executed comes from a string.
I can't do
Select Case StringContainingTheNameOfTheDesiredMethod
Case "Method1"
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i am getting the xml using readxml method. And then display the data in datagrid. But number type columns comes as string type in the dataset. So when datagrid displays , sortingdatagrid columns is not correct. For example it sorts like this:
Salary
1180
12133
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I'm in the process of porting an old excel addin that was writen in VBA to VB .NET. The Excel addin interacts with a number of external com objects. The code sorta looks like this:[code...]
What I'm trying to do is read the string from the COM object and get it in durr for use later in my program.
That second line results in the exception posted above. If I try casting with CStr/CType I get the same exception.
The visual studio watch window reports the type of hurr.getString as a "System.__ComObject" whereas the VBA watch window reports the type as "Variant/Object/String".
Microsoft.VisualBasic.Information.TypeName(hurr.getString) says the type is "String".
my code is :
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The error is Value of type '1-dimensional array of string' cannot be converted to 'String'.
I'm trying to add a new record to my database but i keep getting the message - "conversion from type DBnull to type string is not valid". I think its something to do with the Employee ID when VB attempts to save it to the database my code is below
Imports System.Data.OleDb
Public Class Add
Private Sub DisplayRow()
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I now have SQL Parameters set up and I'm using them to save/delete/add my data. This all works well, except when it's trying to save a combobox to the datatable it appears with the error above.Majority of my comboboxes have datasources, and the valuemembers of these are the actual list items, not the ID's of the list items.I'm not sure why this error could be happening, I'm fairly sure I've connected everything to the binding source correctly; I've checked it a few times.Does anybody know what the cause of this could be? I've looked around a bit and I haven't found much
View 7 RepliesI had write code (just for learning), the codes :
dim Temp as string
Temp = Recordset("
Table_Field")
but, when I start Debugging the error messages "Unable to cast object of type 'ADODB.InternalField' to type 'System.String"
I'm new to VB 2005, the code below is actualy coded from VB 6 and just converted it to VB 2005. I'm having trouble with line that's on bold letters.In VB 6 this works just ok. By the way the error message is "Unable to cast object of type 'System.String' to type 'ADODB.Connection'." [code]
View 5 RepliesI have these errors when creating my website?
Error 1Server Error in '/ Application. -------------------------------------------------------------------------------- Conversion from type 'DBNull' to type 'String' is not valid. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.InvalidCastException: Conversion from type 'DBNull' to type 'String' is not valid. Source Error: Line 64:
Line 65:
how can I solve this error without having to fill all of my fields. Some of the fields in my database are Nulls and some have records.
Error: Conversion from type 'DBNull' to type 'String' is not valid.
I am getting this error No mapping exists from object type System.String[] to a known managed provider native type.The code is
Dim conn1 As SqlConnection
conn1 = New SqlConnection("Data Source=win2008-2;Initial Catalog=h1tm11;User ID=sa;Password=#1cub3123*;Persist Security Info=True;")
' Dim conn1 As String = ConfigurationManager _ .ConnectionStrings("Connectionstring").ConnectionString()
'conn1.ConnectionString = ConfigurationManager.ConnectionStrings("Data Source=win2008-2;Initial Catalog=h1tm11;User ID=sa;
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the error occurs at adapter.Fill(table)
Dim addressstring1 As String = txtpostcode.Value.Trim()
Dim addressstring() As String = Split("addressstring1", ",", 1)
So strings are reference types right? My understanding is a reference to the string in the heap is passed even when you pass the string ByVal to a method.
String myTestValue = "NotModified";
TestMethod(myTestValue);
System.Diagnostics.Debug.Write(myTestValue); /* myTestValue = "NotModified" WTF? *[code].....
And what is going on under the hood? I would have bet my life that the value would have changed....
I am getting the error "Conversion from type 'DataGridViewTextBoxCell' to type 'String' is not valid." When trying to display a cell from DGV in a listbox.I have my variable for the cell reference as follows:
Dim a As Object
a = DataGridView1(4,1)
To insert it in the listbox as follows:
lstLetter.Items.Add(String.Format(a))
I tried:
lstLetter.Items.Add(a)
This will not actually display the entry inside the referenced cell, it shows this in my listbox instead:
DataGridView TextBoxCell { ColumnIndex=4, RowIndex=1 }
how I need to convert this to display.
I was tried to get quantity from db make use of the selection in list box. I got answered with listbox1. If i selected the item in listbox1 the quantity would appear in textbox1. But in this same code will not work for listbox2 with textbox4.. Here i given the code...
$Con.open()
$Dim cd as new oledb.oledbcommand("Select Quantity from tlist where tool_name"& "'"listbox2.selecteditem & "'" & "", con)
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Here i got the error as "Conversion from type DBNull to type string is not valid"
I've been getting this error when pulling data from a recordset. It is coming from a null entry and as a newbie to VB2008 I'm not sure how to get around this.
here is my code lblShipping.Text = reader("CARRIERCODE")
the error:Conversion from type 'DBNull' to type 'String' is not valid. Basically what i'm attempting to accomplish is to see if there is anything in that field. If so put it into the text box if not leave it blank.
Following is my code. Private Structure DISPLAY_ELEMENT_TYPE
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Actually this is vb6 to .net converted code. I m getting compile error at following line
temp = Lset(DispElem(i)) bcz Lset is not supported in .Net Lset accept string data type for first parameter and interger for second.If you know any alternet solution or if you have any source code for Explicit convert UDT to string type and vice versa.
I am having some issue here, and I am not too sure how to handle it. If you could lead me in the right direction
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