int32 | 易学教程

LINQ to Entities does not recognize the method 'Int32 Parse(System.String)' method,

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问题 I am using Entity Framework, and I have a line of code that convert string field (id)to int and compare with a number students = students.Where(s => (Int32.Parse( s.id)>5555)); Whenever I try to run it I receive rhis error. "LINQ to Entities does not recognize the method 'Int32 Parse(System.String)' method, and this method cannot be translated into a store expression." I have tried seveal different things and nothing is working, so any help would be great. 回答1: Firstly I would highly

Cannot perform 'Like' operation on System.Int32 and System.String. DataGridView search and filter

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问题 I have a form that when I select a column name from a ComboBox, and type in a text box it filters and displays the searched criteria in the DataGridView. When I search for "Reference" which is an int data type, which is also identity, and primary key. I get the error message : "Cannot perform 'Like' operation on System.Int32 and System.String." My code is DataTable dt; private void searchForm_Load(object sender, EventArgs e) { SqlCeConnection con = new SqlCeConnection(@"Data Source=

Int to byte array

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问题 I thought .net had some kind of easy conversion method to use for converting an int into a byte array? I did a quick search and all solutions are bit masking/shifting one byte at a time, like "the good ol days". Is there not a ToByteArray() method somewhere? 回答1: byte[] bytes = BitConverter.GetBytes(i); although note also that you might want to check BitConverter.IsLittleEndian to see which way around that is going to appear! Note that if you are doing this repeatedly you might want to avoid

Isn't an Int64 equal to a long in C#?

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问题 I have been playing around with SQL and databases in C# via SqlCeConnection. I have been using ExecuteReader to read results and BigInt values for record IDs which are read into Longs. Today I have been playing with SQL statements that use COUNT based statements ('SELECT COUNT(*) FROM X') and have been using ExecuteScalar to read these single valued results. However, I ran into an issue. I can't seem to store the values into a Long data type, which I have been using up to now. I can store

Double parse with culture format

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I have a double number as string. The number is 202.667,40 Which is 202667.4 How can I parse this string to get the value like: Double.Parse("202.667,40",?what here), or any other method to get the value would be great. Thanks First, you need to know which culture this number is from, then: CultureInfo culture = new CultureInfo("de"); // I'm assuming german here. double number = Double.Parse("202.667,40", culture); If you want to parse using the current thread culture, which by default is the one set for the current user: double number = Double.Parse("202.667,40", CultureInfo.CurrentCulture);

LINQ to Entities does not recognize the method 'Int32 Parse(System.String)' method, and this method cannot be translated into a store expression

阅读更多关于 LINQ to Entities does not recognize the method 'Int32 Parse(System.String)' method, and this method cannot be translated into a store expression

I am using Entity Framework, and I have a line of code that is taking a var and translating it back to an iint for the database. var record = context.enrollments.SingleOrDefault (row => row.userId == int.Parse(UserID) && row.classId == int.Parse(ClassID)); Whenever I try to run it I receive rhis error. "LINQ to Entities does not recognize the method 'Int32 Parse(System.String)' method, and this method cannot be translated into a store expression." I have tried this as well var record = context.enrollments.FirstOrDefault (row => row.userId == Convert.ToInt32(UserID) && row.classId == Convert

Multiplying two positive Int32 returns incorrect, negative answer?

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问题 I'm really stumped on this one. I'm coding in C# for Windows Phone 7.5; I am taking text from a text box, parsing it into an array, then converting each array element into an Int32 using Convert.ToInt32, then running the resulting Int32 values through a series of mathematical calculations, multiplying and adding the Int32 values to hardcoded numbers (all dependent upon what's selected in the UI). All is well until I take the resulting calculations and multiply them together: I'm getting a

Double parse with culture format

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问题 I have a double number as string. The number is 202.667,40 Which is 202667.4 How can I parse this string to get the value like: Double.Parse(\"202.667,40\",?what here), or any other method to get the value would be great. Thanks 回答1: First, you need to know which culture this number is from, then: CultureInfo culture = new CultureInfo("de"); // I'm assuming german here. double number = Double.Parse("202.667,40", culture); If you want to parse using the current thread culture, which by default

LINQ to Entities does not recognize the method 'Int32 Parse(System.String)' method, and this method cannot be translated into a store expression

阅读更多关于 LINQ to Entities does not recognize the method 'Int32 Parse(System.String)' method, and this method cannot be translated into a store expression

问题 I am using Entity Framework, and I have a line of code that is taking a var and translating it back to an iint for the database. var record = context.enrollments.SingleOrDefault (row => row.userId == int.Parse(UserID) && row.classId == int.Parse(ClassID)); Whenever I try to run it I receive rhis error. \"LINQ to Entities does not recognize the method \'Int32 Parse(System.String)\' method, and this method cannot be translated into a store expression.\" I have tried this as well var record =

C# int, Int32 and enums

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问题 If int is synonymous to Int32 why does enum MyEnum : Int32 { Value = 1 } ...not compile? Where as enum MyEnum : int { Value = 1 } will, even though hovering the cursor over the int word will display struct System.Int32? 回答1: The underlying type is indeed the same, but the compiler depends on the type to be as the exact alias. This is a compilation error based on parsing. I took a look at C# grammar specification and the underlying types defined there as tokens based on the alias (e.g. 'int',