blocks|key|1053411|text|The+accepted+answer建议使用cast。但是，大多数SQL类型都有一个特殊的Null字段，可以用来避免这种转换。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1053412|例如，SqlInt32.Null“表示可以分配给SqlInt32类的这个实例的DBNull。”|style|CODE|1053413|int?+example+=+null;
object+exampleCast+=+(object)+example+??+DBNull.Value;
object+exampleNoCast+=+example+??+SqlInt32.Null;|code-block|syntax|javascript|1053414|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/4556007/18192|1|http://msdn.microsoft.com/en-us/library/system.data.sqltypes.sqlint32.null.aspx^0|0|J|0|0|3|D|3|D|1|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|6|7|10|8|@$A|11|B|12|F|G]]|9|@$A|13|B|14|1|15]]|C|$]]|$1|H|3|I|5|J|7|16|8|@]|9|@]|C|$K|L]]|$1|M|3|-4|5|6|7|17|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]|U|$5|P|Q|R|C|$S|V]]]]

<a href="https://stackoverflow.com/a/4556007/18192">The accepted answer</a> suggests making use of a cast. However, most of the SQL types have a special Null field which can be used to avoid this cast. 

For example, <a href="http://msdn.microsoft.com/en-us/library/system.data.sqltypes.sqlint32.null.aspx" rel="noreferrer"><code>SqlInt32.Null</code></a> "Represents a DBNull that can be assigned to this instance of the SqlInt32 class."

<pre><code>int? example = null;
object exampleCast = (object) example ?? DBNull.Value;
object exampleNoCast = example ?? SqlInt32.Null;
</code></pre>

blocks|key|838625|text|除非在存储过程中指定了默认值(如果您正在使用存储过程)，否则需要在SQLCommand中将DBNull.Value作为null参数传递。最好的方法是在查询执行之前为任何缺少的参数分配DBNull.Value，下面的foreach将完成这项工作。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|838626|foreach+(SqlParameter+parameter+in+sqlCmd.Parameters)
{
++++if+(parameter.Value+==+null)
++++{
++++++++parameter.Value+=+DBNull.Value;
++++}
}|code-block|syntax|javascript|838627|否则，请更改此行：|838628|planIndexParameter.Value+=+(AgeItem.AgeIndex==+null)+?+DBNull.Value+:+AgeItem.AgeIndex;|838629|如下所示：|838630|if+(AgeItem.AgeIndex==+null)
++++planIndexParameter.Value+=+DBNull.Value;
else
++++planIndexParameter.Value+=+AgeItem.AgeIndex;|838631|因为您不能在条件语句中使用不同类型的值，因为DBNull和int彼此不同。希望这能有所帮助。|838632|entityMap^0|19|C|2J|C|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|12|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|14|8|@]|D|@]|E|$]]|$1|Q|3|R|5|H|7|15|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|16|8|@]|D|@]|E|$]]|$1|U|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|V|$]]

You need pass <code>DBNull.Value</code> as a null parameter within SQLCommand, unless a default value is specified within stored procedure (if you are using stored procedure). The best approach is to assign <code>DBNull.Value</code> for any missing parameter before query execution, and following foreach will do the job.

<pre><code>foreach (SqlParameter parameter in sqlCmd.Parameters)
{
 if (parameter.Value == null)
 {
 parameter.Value = DBNull.Value;
 }
}
</code></pre>

Otherwise change this line:

<pre><code>planIndexParameter.Value = (AgeItem.AgeIndex== null) ? DBNull.Value : AgeItem.AgeIndex;
</code></pre>

As follows:

<pre><code>if (AgeItem.AgeIndex== null)
 planIndexParameter.Value = DBNull.Value;
else
 planIndexParameter.Value = AgeItem.AgeIndex;
</code></pre>

Because you can't use different type of values in conditional statement, as DBNull and int are different from each other. Hope this will help.

blocks|key|839047|text|只需一行代码，尝试如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|839048|var+piParameter+=+new+SqlParameter("@AgeIndex",+AgeItem.AgeIndex+??+(object)DBNull.Value);|code-block|syntax|javascript|839049|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

With one line of code, try this:

<pre><code>var piParameter = new SqlParameter("@AgeIndex", AgeItem.AgeIndex ?? (object)DBNull.Value);
</code></pre>

blocks|key|1053330|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1053331|SqlParameter[]+parameters+=+new+SqlParameter[1];++++
SqlParameter+planIndexParameter+=+new+SqlParameter("@AgeIndex",+SqlDbType.Int);

planIndexParameter.IsNullable+=+true;+//+Add+this+line

planIndexParameter.Value+=+(AgeItem.AgeIndex==+null)+?+DBNull.Value+:+AgeItem.AgeIndex==+;
parameters[0]+=+planIndexParameter;|code-block|syntax|javascript|1053332|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try this:

<pre><code>SqlParameter[] parameters = new SqlParameter[1]; 
SqlParameter planIndexParameter = new SqlParameter("@AgeIndex", SqlDbType.Int);

planIndexParameter.IsNullable = true; // Add this line

planIndexParameter.Value = (AgeItem.AgeIndex== null) ? DBNull.Value : AgeItem.AgeIndex== ;
parameters[0] = planIndexParameter;
</code></pre>

blocks|key|838886|text|如果使用条件(三元)运算符，编译器需要在两种类型之间进行隐式转换，否则会得到异常。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|838887|因此，您可以通过将两者之一转换为System.Object来修复它|offset|length|style|CODE|838888|planIndexParameter.Value+=+(AgeItem.AgeIndex==+null)+?+DBNull.Value+:+(object)+AgeItem.AgeIndex;|code-block|syntax|javascript|838889|但是，由于结果并不是很好，而且您必须始终记住此类型转换，因此您可以使用这样的扩展方法：|838890|public+static+object+GetDBNullOrValue<T>(this+T+val)
{
++++bool+isDbNull+=+true;
++++Type+t+=+typeof(T);

++++if+(Nullable.GetUnderlyingType(t)+!=+null)
++++++++isDbNull+=+EqualityComparer<T>.Default.Equals(default(T),+val);
++++else+if+(t.IsValueType)
++++++++isDbNull+=+false;
++++else
++++++++isDbNull+=+val+==+null;

++++return+isDbNull+?+DBNull.Value+:+(object)+val;
}|838891|然后，您可以使用以下简洁的代码：|838892|planIndexParameter.Value+=+AgeItem.AgeIndex.GetDBNullOrValue();|838893|entityMap^0|0|G|D|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@$D|Y|E|Z|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|10|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|11|8|@]|9|@]|A|$]]|$1|O|3|P|5|J|7|12|8|@]|9|@]|A|$K|L]]|$1|Q|3|R|5|6|7|13|8|@]|9|@]|A|$]]|$1|S|3|T|5|J|7|14|8|@]|9|@]|A|$K|L]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

If you use the conditional(ternary) operator the compiler needs an implicit conversion between both types, otherwise you get an exception. 

So you could fix it by casting one of both to <code>System.Object</code>:

<pre><code>planIndexParameter.Value = (AgeItem.AgeIndex== null) ? DBNull.Value : (object) AgeItem.AgeIndex;
</code></pre>

But since the result is not really pretty and you always have to remember this casting, you could use such an extension method instead:

<pre><code>public static object GetDBNullOrValue&lt;T&gt;(this T val)
{
 bool isDbNull = true;
 Type t = typeof(T);

 if (Nullable.GetUnderlyingType(t) != null)
 isDbNull = EqualityComparer&lt;T&gt;.Default.Equals(default(T), val);
 else if (t.IsValueType)
 isDbNull = false;
 else
 isDbNull = val == null;

 return isDbNull ? DBNull.Value : (object) val;
}
</code></pre>

Then you can use this concise code:

<pre><code>planIndexParameter.Value = AgeItem.AgeIndex.GetDBNullOrValue();
</code></pre>

blocks|key|838540|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|838541|if+(AgeItem.AgeIndex+!=+null)
{
+++SqlParameter[]+parameters+=+new+SqlParameter[1];
+++SqlParameter+planIndexParameter+=+new+SqlParameter("@AgeIndex",+SqlDbType.Int);
+++planIndexParameter.Value+=+AgeItem.AgeIndex;
+++parameters[0]+=+planIndexParameter;
}|code-block|syntax|javascript|838542|换句话说，如果参数为null，就不要将其发送到存储的proc+(当然，假设存储的proc接受null参数，这在您的问题中是隐含的)。|838543|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Try this:

<pre><code>if (AgeItem.AgeIndex != null)
{
 SqlParameter[] parameters = new SqlParameter[1];
 SqlParameter planIndexParameter = new SqlParameter("@AgeIndex", SqlDbType.Int);
 planIndexParameter.Value = AgeItem.AgeIndex;
 parameters[0] = planIndexParameter;
}
</code></pre>

In other words, if the parameter is null just don't send it to your stored proc (assuming, of course, that the stored proc accepts null parameters which is implicit in your question).

blocks|key|838575|text|在我看来，更好的方法是使用SqlCommand类的Parameters属性：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|838576|public+static+void+AddCommandParameter(SqlCommand+myCommand)
{
++++myCommand.Parameters.AddWithValue(
++++++++"@AgeIndex",
++++++++(AgeItem.AgeIndex==+null)+?+DBNull.Value+:+AgeItem.AgeIndex);
}|code-block|syntax|javascript|838577|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand%2528v=vs.80%2529.aspx|1|http://msdn.microsoft.com/en-US/library/system.data.sqlclient.sqlcommand.parameters%2528v=VS.80%2529.aspx^0|D|A|0|P|A|1|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]|$A|W|B|X|1|Y]]|C|$]]|$1|D|3|E|5|F|7|Z|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|10|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]|Q|$5|L|M|N|C|$O|R]]]]

In my opinion the better way is to do this with the <a href="http://msdn.microsoft.com/en-US/library/system.data.sqlclient.sqlcommand.parameters%28v=VS.80%29.aspx" rel="nofollow">Parameters</a> property of the <a href="http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand%28v=vs.80%29.aspx" rel="nofollow">SqlCommand</a> class:

<pre><code>public static void AddCommandParameter(SqlCommand myCommand)
{
 myCommand.Parameters.AddWithValue(
 "@AgeIndex",
 (AgeItem.AgeIndex== null) ? DBNull.Value : AgeItem.AgeIndex);
}
</code></pre>

blocks|key|838768|text|if+(_id_categoria_padre+>+0)
{
++++objComando.Parameters.Add("id_categoria_padre",+SqlDbType.Int).Value+=+_id_categoria_padre;
}
else
{
++++objComando.Parameters.Add("id_categoria_padre",+DBNull.Value).Value+=+DBNull.Value;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|838769|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>if (_id_categoria_padre &gt; 0)
{
 objComando.Parameters.Add("id_categoria_padre", SqlDbType.Int).Value = _id_categoria_padre;
}
else
{
 objComando.Parameters.Add("id_categoria_padre", DBNull.Value).Value = DBNull.Value;
}
</code></pre>

blocks|key|838801|text|考虑使用可用的Nullable(T)结构。它只允许您在有值的情况下设置这些值，并且您的SQL+Command对象将识别可为空的值并相应地进行处理，而不会对您造成任何麻烦。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|838802|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Consider using the Nullable(T) structure available. It'll let you only set values if you have them, and your SQL Command objects will recognize the nullable value and process accordingly with no hassle on your end.

blocks|key|838945|text|一个简单的扩展方法是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|838946|++++public+static+void+AddParameter(this+SqlCommand+sqlCommand,+string+parameterName,+
++++++++SqlDbType+sqlDbType,+object+item)
++++{
++++++++sqlCommand.Parameters.Add(parameterName,+sqlDbType).Value+=+item+??+DBNull.Value;
++++}|code-block|syntax|javascript|838947|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

A simple extension method for this would be:

<pre><code> public static void AddParameter(this SqlCommand sqlCommand, string parameterName, 
 SqlDbType sqlDbType, object item)
 {
 sqlCommand.Parameters.Add(parameterName, sqlDbType).Value = item ?? DBNull.Value;
 }
</code></pre>

blocks|key|839008|text|我使用了一个带有null检查的简单方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|839009|++++public+SqlParameter+GetNullableParameter(string+parameterName,+object+value)
++++{
++++++++if+(value+!=+null)
++++++++{
++++++++++++return+new+SqlParameter(parameterName,+value);
++++++++}
++++++++else
++++++++{
++++++++++++return+new+SqlParameter(parameterName,+DBNull.Value);
++++++++}
++++}|code-block|syntax|javascript|839010|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I use a simple method with a null check.

<pre><code> public SqlParameter GetNullableParameter(string parameterName, object value)
 {
 if (value != null)
 {
 return new SqlParameter(parameterName, value);
 }
 else
 {
 return new SqlParameter(parameterName, DBNull.Value);
 }
 }
</code></pre>

blocks|key|839098|text|我的代码，在实际工程中看起来是三元操作符，在做for参数之前，这对我来说是最好的方法，没有问题：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|839099|++++public+bool+Key_AddExisting
++++(
++++++++++string+clave
++++++++,+int?+idHito_FileServer
++++++++,+int?+idTipoDocumental_Almacen
++++++++,+string+tipoExp_CHJ
++++++++,+int+idTipoExp_Verti2
++++++++,+int+idMov_Verti2
++++)
++++{
++++++++List<SqlParameter>+pars+=+new+List<SqlParameter>()
++++++++{
++++++++++++++new+SqlParameter+{+ParameterName+=+"@Clave",+Value+=+clave+}
++++LOOK+->+,+idHito_FileServer+==+null+?+new+SqlParameter+{+ParameterName+=+"@IdHito_FileServer",+Value+=+DBNull.Value+}+:+new+SqlParameter+{+ParameterName+=+"@IdHito_FileServer",+Value+=+idHito_FileServer+}
++++LOOK+->+,+idTipoDocumental_Almacen+==+null+?+new+SqlParameter+{+ParameterName+=+"@IdTipoDocumental_Almacen",+Value+=+DBNull.Value+}+:+new+SqlParameter+{+ParameterName+=+"@IdTipoDocumental_Almacen",+Value+=+idTipoDocumental_Almacen+}
++++++++++++,+new+SqlParameter+{+ParameterName+=+"@TipoExp_CHJ",+Value+=+tipoExp_CHJ+}
++++++++++++,+new+SqlParameter+{+ParameterName+=+"@IdTipoExp_Verti2",+Value+=+idTipoExp_Verti2+}
++++++++++++,+new+SqlParameter+{+ParameterName+=+"@IdMov_Verti2",+Value+=+idMov_Verti2+}
++++++++};

++++++++string+sql+=+"INSERT+INTO+[dbo].[Enlaces_ClavesCHJ_MovimientosVerti2]+"+%2B
++++++++++++"(+"+%2B
++++++++++++"++[Clave]+"+%2B
++++++++++++",+[IdHito_FileServer]+"+%2B
++++++++++++",+[IdTipoDocumental_Almacen]+"+%2B
++++++++++++",+[TipoExp_CHJ]+"+%2B
++++++++++++",+[IdTipoExp_Verti2]+"+%2B
++++++++++++",+[IdMov_Verti2]+"+%2B
++++++++++++")+"+%2B
++++++++++++"VALUES"+%2B
++++++++++++"(+"+%2B
++++++++++++"++@Clave"+%2B
++++++++++++",+@IdHito_FileServer"+%2B
++++++++++++",+@IdTipoDocumental_Almacen"+%2B
++++++++++++",+@TipoExp_CHJ"+%2B
++++++++++++",+@IdTipoExp_Verti2"+%2B
++++++++++++",+@IdMov_Verti2"+%2B
++++++++++++")";

++++++++return+DbBasic.ExecNonQuery(ref+this.conn,+sql,+pars);
++++}|code-block|syntax|javascript|839100|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

My code, working in real project
Look the ternary operator beafore make the sqlparameter
this is the best way for me, withou problems:

<pre><code> public bool Key_AddExisting
 (
 string clave
 , int? idHito_FileServer
 , int? idTipoDocumental_Almacen
 , string tipoExp_CHJ
 , int idTipoExp_Verti2
 , int idMov_Verti2
 )
 {
 List&lt;SqlParameter&gt; pars = new List&lt;SqlParameter&gt;()
 {
 new SqlParameter { ParameterName = "@Clave", Value = clave }
 LOOK -&gt; , idHito_FileServer == null ? new SqlParameter { ParameterName = "@IdHito_FileServer", Value = DBNull.Value } : new SqlParameter { ParameterName = "@IdHito_FileServer", Value = idHito_FileServer }
 LOOK -&gt; , idTipoDocumental_Almacen == null ? new SqlParameter { ParameterName = "@IdTipoDocumental_Almacen", Value = DBNull.Value } : new SqlParameter { ParameterName = "@IdTipoDocumental_Almacen", Value = idTipoDocumental_Almacen }
 , new SqlParameter { ParameterName = "@TipoExp_CHJ", Value = tipoExp_CHJ }
 , new SqlParameter { ParameterName = "@IdTipoExp_Verti2", Value = idTipoExp_Verti2 }
 , new SqlParameter { ParameterName = "@IdMov_Verti2", Value = idMov_Verti2 }
 };

 string sql = "INSERT INTO [dbo].[Enlaces_ClavesCHJ_MovimientosVerti2] " +
 "( " +
 " [Clave] " +
 ", [IdHito_FileServer] " +
 ", [IdTipoDocumental_Almacen] " +
 ", [TipoExp_CHJ] " +
 ", [IdTipoExp_Verti2] " +
 ", [IdMov_Verti2] " +
 ") " +
 "VALUES" +
 "( " +
 " @Clave" +
 ", @IdHito_FileServer" +
 ", @IdTipoDocumental_Almacen" +
 ", @TipoExp_CHJ" +
 ", @IdTipoExp_Verti2" +
 ", @IdMov_Verti2" +
 ")";

 return DbBasic.ExecNonQuery(ref this.conn, sql, pars);
 }
</code></pre>

blocks|key|838664|text|尝试如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|838665|if+(_id_categoria_padre+>+0)
{
++++objComando.Parameters.Add("id_categoria_padre",+SqlDbType.Int).Value+=+_id_categoria_padre;
}
else
{
++++objComando.Parameters.Add("id_categoria_padre",+DBNull.Value).Value+=+DBNull.Value;
}|code-block|syntax|javascript|838666|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

try something like this:

<pre class="lang-cs prettyprint-override"><code>if (_id_categoria_padre &gt; 0)
{
 objComando.Parameters.Add("id_categoria_padre", SqlDbType.Int).Value = _id_categoria_padre;
}
else
{
 objComando.Parameters.Add("id_categoria_padre", DBNull.Value).Value = DBNull.Value;
}
</code></pre>

blocks|key|1053451|text|int?+nullableValue+=+null;
object+nullableValueDB
{
+++get{
+++++++if(nullableValue==null)
++++++++++return+DBNull.Value;
+++++++else
++++++++++return+(int)nullableValue;
+++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1053452|我就是这样解决的。|unstyled|1053453|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>int? nullableValue = null;
object nullableValueDB
{
 get{
 if(nullableValue==null)
 return DBNull.Value;
 else
 return (int)nullableValue;
 }
}
</code></pre>

I'm solving like that.

blocks|key|1053476|text|if+(AgeItem.AgeIndex==+null)++
++++cmd.Parameters.Add(new+SqlParameter("ParaMeterName",+SqlDbType.DateTime).Value+=+DBNull);++
else++
++++cmd.Parameters.Add(new+SqlParameter("ParaMeterName",+SqlDbType.DateTime).Value+=+AgeItem.AgeIndex);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1053477|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>if (AgeItem.AgeIndex== null) 
 cmd.Parameters.Add(new SqlParameter("ParaMeterName", SqlDbType.DateTime).Value = DBNull); 
else 
 cmd.Parameters.Add(new SqlParameter("ParaMeterName", SqlDbType.DateTime).Value = AgeItem.AgeIndex);
</code></pre>

blocks|key|838825|text|这就是我要做的..。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|838826|++++++++var+PhoneParam+=+new+SqlParameter("@Phone",+DBNull.Value);
++++++++if+(user.User_Info_Phone+!=+null)
++++++++{
++++++++++++PhoneParam.SqlValue+=+user.User_Info_Phone;
++++++++}

++++++++return+this.Database.SqlQuery<CustLogonDM>("UpdateUserInfo+@UserName,+@NameLast,+@NameMiddle,+@NameFirst,+@Address,+@City,+@State,+@PostalCode,+@Phone",
++++++++++++UserNameParam,+NameLastParam,+NameMiddleParam,+NameFirstParam,+AddressParam,+CityParam,+StateParam,+PostalParam,+PhoneParam).Single();|code-block|syntax|javascript|838827|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This is what I simply do...

<pre><code> var PhoneParam = new SqlParameter("@Phone", DBNull.Value);
 if (user.User_Info_Phone != null)
 {
 PhoneParam.SqlValue = user.User_Info_Phone;
 }

 return this.Database.SqlQuery&lt;CustLogonDM&gt;("UpdateUserInfo @UserName, @NameLast, @NameMiddle, @NameFirst, @Address, @City, @State, @PostalCode, @Phone",
 UserNameParam, NameLastParam, NameMiddleParam, NameFirstParam, AddressParam, CityParam, StateParam, PostalParam, PhoneParam).Single();
</code></pre>

blocks|key|838842|text|++++++++++++dynamic+psd+=+DBNull.Value;

++++++++++++if+(schedule.pushScheduleDate+>+DateTime.MinValue)
++++++++++++{
++++++++++++++++psd+=+schedule.pushScheduleDate;
++++++++++++}


++++++++++++sql.DBController.RunGeneralStoredProcedureNonQuery("SchedulePush",
+++++++++++++++++++++new+string[]+{+"@PushScheduleDate"},
+++++++++++++++++++++new+object[]+{+psd+},+10,+"PushCenter");|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|838843|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> dynamic psd = DBNull.Value;

 if (schedule.pushScheduleDate &gt; DateTime.MinValue)
 {
 psd = schedule.pushScheduleDate;
 }


 sql.DBController.RunGeneralStoredProcedureNonQuery("SchedulePush",
 new string[] { "@PushScheduleDate"},
 new object[] { psd }, 10, "PushCenter");
</code></pre>

The following code gives an error - "No implicit conversion from DBnull to int."

<pre><code>SqlParameter[] parameters = new SqlParameter[1]; 
SqlParameter planIndexParameter = new SqlParameter("@AgeIndex", SqlDbType.Int);
planIndexParameter.Value = (AgeItem.AgeIndex== null) ? DBNull.Value : AgeItem.AgeIndex;
parameters[0] = planIndexParameter;
</code></pre>

Assign null to a SqlParameter

编译器

下面的代码给出了一个错误--“没有从DBnull到int的隐式转换”。SqlParameter[] parameters = new SqlParameter[1];    SqlParameter planIndexParameter = new SqlParameter("@AgeIndex", SqlDbType.Int);planIndexParameter.Value = (AgeIte

问将null赋值给SqlParameter
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问将null赋值给SqlParameter
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