请问什么是错误功能 [英] Please what is the error function

问题描述

public Byte[] picbox(string  p)
 {
        byte[] binaryData;
        connection.Open();
        command.CommandText = "select * From adduser where (bakernum=@bakernum)";
        command.Parameters.AddWithValue("@bakernum", p);
         SqlDataReader reader = command.ExecuteReader();
         reader.Read();
         if (reader.HasRows)
            binaryData = (byte[])reader.GetValue(14);
        return binaryData ;
  }

我想返回binaryData，但是不能.
binaryData从Sql2008R2中读取fild varbinary(max).
varbinary归档的是图片或图像到db.
错误是:(局部变量)byte [] binaryData
ERRoR:
使用未分配的局部变量"binaryData"

i want return binaryData .but cant.
binaryData read fild varbinary(max) from Sql2008R2.
varbinary filed is picture or image to db.
error is :(local variable) byte[] binaryData
ERRoR:
use of unassigned local variable ''binaryData''
thanks.

推荐答案

将binaryData 初始化为null.

Initialize binaryData to null.

byte[] binaryData = null;

而且，如果您不想调用代码来处理null，请将其初始化为零长度的数组.

And if you don''t want calling code to handle a null, initialize it to a zero length array.

byte[] binaryData = new byte[0];

发生编译器错误的原因是，如果您不输入if块，则它是一个代码分支，其中局部变量保持未初始化状态(这会破坏C#规则，从而导致错误).

The reason for the compiler error is that if you don''t enter the if-block, then it''s a code-branch where the local variable remains uninitialized (which breaks C# rules, and hence the error).

您需要创建一个属性以返回二进制值...
您最好返回任何值...

You need to create a property to return a binary value...
It is more better for you to return any value...

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