“字符串"不包含"IsNullOrWhiteSpace"的定义如何解决此错误? [英] 'string' does not contain a definition for 'IsNullOrWhiteSpace' how to solve this error?

问题描述

谁能知道.

它显示错误，如字符串"不包含"IsNullOrWhiteSpace"的定义如何解决此错误?

Can anyone know.

it show error like ,''string'' does not contain a definition for ''IsNullOrWhiteSpace'' how to solve this error?

public object SQLExecuteNonQuery(string procedureName, Hashtable cmdParms)
   {
       try
       {
           _SqlConnection = GetSQLConnection();
           //Open SQL Connection
           _SqlConnection.Open();
           _SqlCommand = new SqlCommand(procedureName, _SqlConnection);

           _SqlCommand.CommandType = CommandType.StoredProcedure;
           //null or empty checking procdure name and hashtable
           if (cmdParms.Count > 0 && !string.IsNullOrWhiteSpace(procedureName))
           {
               foreach (DictionaryEntry de in cmdParms)
               {
                   //adding sql parameter
                   _SqlCommand.Parameters.Add(new SqlParameter(de.Key.ToString(), de.Value));
               }

           }
           //Executing SQl Command
           return _SqlCommand.ExecuteScalar();
       }

推荐答案

string.IsNullOrWhiteSpace已添加到.net Framework 4.0及更高版本中.因此，您必须使用旧版本的.net框架.在项目设置中设置适当的.net框架.请参见此处 [

string.IsNullOrWhiteSpace was added to .net framework 4.0 and up. So you must be using older version of .net framework. Set the appropriate .net framework in your project settings. See here[^].

看起来像你尝试在旧版本的.Net中构建代码.
.NET 4.0之前的任何版本都不支持此方法.

Looks like you are trying to build code in an older version of .Net.
Anything before .Net 4.0 does not support this method.

String.NET 4中引入了IsNullOrWhiteSpace.如果您不针对.NET 4，则可以轻松编写自己的代码:

String.IsNullOrWhiteSpace has been introduced in .NET 4. If you are not targeting .NET 4 you could easily write your own:

public static class StringExtensions
{
    public static bool IsNullOrWhiteSpace(string value)
    {
        if (value != null)
        {
            for (int i = 0; i < value.Length; i++)
            {
                if (!char.IsWhiteSpace(value[i]))
                {
                    return false;
                }
            }
        }
        return true;
    }
}

可以这样使用:

bool isNullOrWhiteSpace = StringExtensions.IsNullOrWhiteSpace("foo bar");

which could be used like this:

bool isNullOrWhiteSpace = StringExtensions.IsNullOrWhiteSpace("foo bar");

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