100165605.htm

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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">Char</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">Int16</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">Single</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">UInt32</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">DateTime</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">Int32</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">String</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">UInt64</span></p>
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<p class="MsoNormal" style="MARGIN-TOP: 8.15pt"><span style="FONT-FAMILY: 宋体">一旦创建好，就要给</span><span lang="EN-US">DataColumn</span><span style="FONT-FAMILY: 宋体">对象设置其他属性，例如该列是否可为空或者设置默认值。下面的代码段显示了给</span><span lang="EN-US">DataColumn</span><span style="FONT-FAMILY: 宋体">设置的一些常见选项：</span></p>
<p class="2" style="MARGIN-TOP: 8.15pt; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US">DataColumn customerID = new DataColumn(&quot;CustomerID&quot; , typeof(int));</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US">customerID.AllowDBNull = false;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US">customerID.ReadOnly = false;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US">customerID.AutoIncrement = true;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US">customerID.AutoIncrementSeed = 1000;</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US">DataColumn name = new DataColumn(&quot;Name&quot; , typeof(string));</span></p>
<p class="2" style="MARGIN-LEFT: 21.45pt; FTEL: 18.45pt"><span lang="EN-US">name.AllowDBNull = false;</span></p>
<p class="2" style="MARGIN-TOP: 0cm; MARGIN-LEFT: 21.45pt; MARGIN-RIGHT: 0cm; FTEL: 18.45pt"><span lang="EN-US">name.Unique = true;</span></p>
<p class="MsoNormal"><span style="FONT-FAMILY: 宋体">可以给</span><span lang="EN-US">DataColumn</span><span style="FONT-FAMILY: 宋体">设置如表</span><span lang="EN-US">21-4</span><span style="FONT-FAMILY: 宋体">所示的属性。</span></p>
<p class="a5" style="MARGIN-TOP: 8.15pt"><span style="FONT-FAMILY: 黑体">表</span><span lang="EN-US">&nbsp; 21-4</span></p>
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            <p class="a2"><span style="FONT-FAMILY: 黑体">属</span><span lang="EN-US">&nbsp;&nbsp;&nbsp; </span><span style="FONT-FAMILY: 黑体">性</span></p>
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            <p class="a2"><span style="FONT-FAMILY: 黑体">说</span><span lang="EN-US">&nbsp;&nbsp;&nbsp; </span><span style="FONT-FAMILY: 黑体">明</span></p>
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            <td style="BORDER-RIGHT: windowtext 1pt solid; PADDING-RIGHT: 9.9pt; PADDING-LEFT: 9.9pt; PADDING-BOTTOM: 0cm; WIDTH: 108.55pt; BORDER-TOP-STYLE: none; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT-STYLE: none" valign="top" width="145">
            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">AllowDBNull</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span style="FONT-FAMILY: 宋体">如果为</span><span lang="EN-US">true</span><span style="FONT-FAMILY: 宋体">，该列就可以设置为</span><span lang="EN-US">DBNull</span></p>
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            <td style="BORDER-RIGHT: windowtext 1pt solid; PADDING-RIGHT: 9.9pt; PADDING-LEFT: 9.9pt; PADDING-BOTTOM: 0cm; WIDTH: 108.55pt; BORDER-TOP-STYLE: none; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 1pt solid; BORDER-LEFT-STYLE: none" valign="top" width="145">
            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">AutoIncrement</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span style="FONT-FAMILY: 宋体">定义自动生成的列值为一个递增的数字</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">AutoIncrementSeed</span></p>
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            <td style="PADDING-RIGHT: 9.9pt; PADDING-LEFT: 9.9pt; PADDING-BOTTOM: 0cm; WIDTH: 333.9pt; BORDER-TOP-STYLE: none; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 1pt solid; BORDER-RIGHT-STYLE: none; BORDER-LEFT-STYLE: none" valign="top" width="445">
            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span style="FONT-FAMILY: 宋体">定义</span><span lang="EN-US">AutoIncrement</span><span style="FONT-FAMILY: 宋体">列最初的种子值</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">AutoIncrementStep</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span style="FONT-FAMILY: 宋体">用默认的步骤定义自动生成列值的步骤</span></p>
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            <p class="a4" style="MARGIN-LEFT: 10.7pt"><span lang="EN-US">Caption</span></p>
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