如何使用C#在访问表中设置默认值 [英] how to set default value in access table using C#

问题描述

如何使用C#在访问表中设置默认值
我想添加默认值="

how to set default value in access table using C#
I want add default value=""

Catalog cat = new Catalog();                                
                string strCreateDB = "";
                strCreateDB += "Provider=Microsoft.Jet.OLEDB.4.0;";
                strCreateDB += "Data Source=" + strPath + ";";
                strCreateDB += "Jet OLEDB:Engine Type=5";
                cat.Create(strCreateDB);
                Table tblPhases = new Table();
                tblPhases.Name = "tblPhases";
                ADOX.Column objCol = new Column();                
                objCol.Name = "PhaseID";
                tblPhases.Columns.Append(objCol, ADOX.DataTypeEnum.adInteger);
                tblPhases.Keys.Append("PhaseIDPrimaryKey", KeyTypeEnum.adKeyPrimary, objCol);
                tblPhases.Columns.Append("PhaseCaption", DataTypeEnum.adVarWChar, 255);
              
                tblPhases.Columns.Append("PhaseDesc", DataTypeEnum.adVarWChar, 255);
                cat.Tables.Append(tblPhases);

推荐答案

Access数据库字段的默认值由数据库设置为 NonExistant Value 不等于"或C#为null.它是 DBNull.Value

另一方面，如果要在数据集中设置默认值，请转到数据集设计器并选择所需表的所需列.然后，使用 DataColumn 的 DefaultValue 属性，可以在属性窗口中将字段类型为字符串的默认值设置为".

The default value of Access database field is set by database to NonExistant Value which is not equal to "" or null of C#. It is DBNull.Value

On the other hand if you want to set a default value in the dataset, go to dataset designer and select the required column of the required table. Then from the properties window you can set the default value to "" if the field type is string, using the DefaultValue property of the DataColumn.

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