Failed to enable constraints. One or more rows contain values violating nonnull, unique, or foreignkey constraints.

遇到这个错误 Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.

请参考msdn文章来debug找出错误的地方: http://msdn.microsoft.com/en-us/library/system.data.datatable.geterrors(VS.71).aspx

它检查DataSet中的所有DataTable的HasErrors属性，然后对有错误的DataTable使用GetErrors方法。

GetErrors返回一组DataRows，检查返回的所有DataRow的RowError属性来获得确切的错误信息。

 

举例如下:

 try
{
   SqlDataAdapter.Fill(dataTable);  //这行会出错,先catch住
}
catch{}

 

//remove datatable errors 
DataRow[] rowsInError;
if (dataTable.HasErrors)
{
                // Get an array of all rows with errors.
                rowsInError = dataTable.GetErrors();
                // Print the error of each column in each row.
                StringBuilder sbError = new StringBuilder();
                for (int i = 0; i < rowsInError.Length; i++)
                {
                    foreach (DataColumn myCol in dataTable.Columns)
                    {
                        sbError.Append(myCol.ColumnName + " " + rowsInError[i].GetColumnError(myCol));
                    }
                    // Clear the row errors
                    rowsInError[i].ClearErrors();
                }
}

 

最后sbError打印出来后就是一堆文字:

{id name title Column 'title' exceeds the MaxLength limit.  desc publishdate...}

可以很清楚的看到,是title字段超长了.